Since I'm bored I decided to put together a small guide for Martial Arts engineers. There is no such guide in the forums yet afaik, and maybe someone is going to read it.
Why MA Engineer?
In my opinion MA is a good alternative way for the PvM DD whoring engi from the usual Dual ql 300 peregrine one. It is a little cheaper on the equipment compared to pistols, while still offering impressive DPS rates. You have to keep in mind though that it is more suited for PvM and probably not the best choice for PvP. With a swapped in bow you can even participate in the AS wars, but you will loose the maximum PvM dmg capability by not being able to use two shen sticks.
Levelling as MA engineer
When I created my engineer in May 2005 I did it with the sole purpose of going the MA way. So I used MA all the way up from level 1-220. Looking back I can say that it is not an optimal weapon choice for low and mid levels. At those levels being at melee range is a serious drawback. Dmg is also far from impressive. At around level 210 it becomes a lot better, as you then have the HP you need to take some hits and can also equip ql 300 Combined Mercenaries armor. Overall I think it is better suited as endgame choice. If you want to be a top notch DD at every level range, you better use pistols and/or grenade until you do the switch over to MA.
Which Breed to choose?
Each breed has it's advantages and disadvantages. Nanomage is the only breed I would NOT recommend if you want to make a MA engineer. Not only because of the lower hp, but also because of the very low STR/STA values. As a Nanomage it will be impossible to self equip ql 300 Combined mercenary's armor without making huge sacrifices in your perk setup. Not being able to swap out your armor will make casting your bots a pain in the ass.
Opifex has the highest base MA skill of the 4 breeds. This comes at the cost of low STA, which will again make selfing ql 300 Mercenary's armor very hard.
Atrox have the easiest time equipping mercenary's armor, but due to the low PSY their base MA skill is the second lowest of all breeds. Also the Arithmetic armor you can use will be lower ql than what other breeds can get on, but that's not a big issue in my opinion.
I chose solitus. The main reason was the balanced abilities. Since I wanted to reach the maximum possible dmg with martial arts, I had to do without the right-hand and eye symbiant. The loss in nano abilities I had to cover with being able to swap my armor whenever I needed to. Maintaining 1k Str/Sta while still being able to equip reasonably high ql Arithmetic armor is easiest to achieve with Solitus in my opinion. The 18 points lower MA skill compared to Opifex at level 220 is something I can live with.
As a conclusion to the breed choice I think it's safe to say that you can pick whichever breed you want, as long as you are able to selfequip your armor. The difference in MA skill is very small at level 220, so it shouldn't be your main focus when you choose your breed. No matter which one you pick, they all are able to reach 2k+ without towers/contracts.
Which Skills?
The skills you will want to max are Martial arts and Brawling. Brawling may seem like a very gimpy special, but it's the only one you get. At level 220 I have about 1.4k brawl skill and the hits average around 2k dmg per hit, so I think it's well worth the IP investment. The Brawl recharge time is fixed at 15s, more skill does not reduce the time. However Brawl has its own AR. Meaning the more Brawl skill you have, the higher your chance to hit and your dmg per hit.
Dimach I raised only a bit to meet the requirements for the shen sticks.
I raised parry to 1k, so I can use a ql 215 Blessed with thunder for additional dmg. If you got the IP to spare and want to use higher ql MA attacks, you can of course put in more points.
The same goes for Physical Init. Put in what you can afford to invest. Personally I don't have a lot of IP in it, only enough to make me hit 1/1 at full agg. If you do a lot of soloing/tanking, you can raise it to be able to stay more def with still being able to hit 1/1. On the other hand I found it useful to hit slower while being full def to give the bot a chance to hold aggro when I solo.
Do I need to raise evades?
Personally I don't think that evades are of much use on an engineer. I only raised them to around 500ish (with the berserk implant installed). Together with the new spirit infused Yutto NCUs I don't get critted that much, I even avoid some hits in inferno hard missions. If you want to, you can still max them, but I think if you want to skill for PvP too you will have to dump your tradeskills.
Can I still use tradeskills as MA engineer?
Yes, it's possible to keep your tradeskills and still raise all skills needed to perform well as MA engi. In my current setup I can make everything, but it takes a little more effort than for a pure TS engi. The only Tradeskill I did not raise is Psychology, cause I have a crat on the same account to take care of that. Also I tried not to dump too much IP into the tradeskills in general. In my Tradeskill outfit using the HQ machine I got pretty much exactly the amount of skill I need.
Still about 3.5mil IP left, so it is theoretically possible to max all evades and psychology too. I want to leave a little room though in case FC invents some new things that need IP spending in other areas.
Which buffs are useful?
The most useful buff we can cast ourselves: Slayerdroid Transference will boost your MA skill by 300 points. This is the buff that makes the whole martial arts idea work.
Other buffs you should ask for when teamed/buff begging:
Lesser controlled rage (+12 MA, cast by MA)
Martial arts Mastery (+60 MA, cast by MA)
Mark of Peril (+7 crit, cast by MA)
Take the shot (+4 crit, cast by Agent)
Dirty Fighter (+45 to Brawl, cast by MA)
And of course anything that adds to your offense and +dmg is good too. Crat and keeper auras can make a huge difference for the DD output you will have.
Which Perks?
This is my perk setup at level 220/23:
I put 10 points in mechanic. The AC drain is pretty nice in my opinion. It helps the bots to break the min dmg barrier sometimes and it also helps with the fist attacks, which have a very high max dmg value.
10 points in shotgun mastery for the +dmg.
10 points in bioshielding.
5 points in Kungfu master. (This Perkline also gives you a nice 2-3k heal perk at level 5)
5 points in Ambidextrous also for the +dmg.
10 points in Champion of light infantry.
10 points in Champion of nano combat.
3 points in AI tech.
This is maybe not be the best setup for your playing style, but it works for me. You can always adjust the perks to suit your current needs. Maybe put a few points into Freak str to self the armor earlier.
Which symbiants/Implants to use?
It is pretty obvious, but of course you will want Right-hand, left-hand and feet implants instead of symbiants for the added MA. In the eye slot an Exterminator Occular Enhancement instead of the symbiant also gives a nice boost to the dmg output. I waited with the exterminator occular until I was finished twinking on the other high level symbiants though.
In situations where you don't have to tank, the Ethereal Implant of Berserker Rage in the Left-Arm slot is also very nice. I use a ql 240 left-arm symbiant instead of the berserker implant if I know I'm gonna take a lot of dmg (Soloing for example).
When I started to go for the Shen sticks I replaced the right- and left-wrist symbiants with ql 270-290ish multimelee implants. If you want to get the max benefit from these slots it's possible to put in +energy dmg clusters.
Should I focus on +dmg or +crit items for the best Dmg output?
To see what is better in a certain slot, you have to compare your average dmg per normal hit with your average dmg when critting. When using Martial arts the average crit is usually about 2k higher than the average normal hit. One point crit increase means you will crit once more in 100 hits. That equals to 2000dmg/100=20 dmg, meaning each +crit gives you +20dmg.
If you now take for example the shoulderslot, you got the choice between a Globe of clarity, a Might of the Revenant and a Barrow Strength. Globe of clarity gives 1 crit (+20 dmg), MoR gives +32 dmg and Barrow Strength +15 dmg. This makes MoR the best choice, followed by GoC and then Barrow strength. As you can, see the difference between a GoC and a Barrow Strength is not much, making the Barrow Strength a great low budget choice if you don't want to spend 200mil+ on a Goc.
Another example for the back item slot: Lets compare a RBP with a Spirit shroud of the artillery. RBP adds +60 dmg, but only to energy dmg. That means it will only affect your weapon hits (BoB or Shen stick), making it give you +60dmg*.66=+40dmg if you are wearing two weapons. The Spirit shroud adds +1 crit, about +20dmg, but to all attacks. So we can see that a RBP is twice as good as a spirit shroud dmg wise.
Another important factor is the new martial arts weapon template you will get once you go past 2k MA skill. On low AC mobs going from like 1990 to 2010 will increase your fist crit dmg by about 250 points. This means you should focus on getting past 2k first, before you start adding +dmg items while sacrificing a few points in MA skill. Without towers and/or contracts this will be an issue for 220 engineers only. So if you can't go past 2k MA skill anyway, you can let your MA skill drop a few points in favor of more +dmg.
Which Armor?
From low levels to late TL5 I wouldn't worry too much about Martial arts specific armor. Go for the standard armors, like Carbonum, Tier or maybe OFAB. Being able to cast your bots should always have top priority at those levels. If you want some MA adding armor for your midlevels, the new Rhinoman Armor introduced in 17.4 is also an option.
For TL 6 and upwards, Combined Mercenary's with a Dchest in the chest slot is the obvious choice, as it offers both Weapon skills and HP. If you want to use something cheaper, you can go for a Cuirass of obstinacy. It goes for usually under 20 points in RK 2 beast raids.
Until you get the helmet upgrade from sector 13 you can use a Predator's circlet in that slot if you don't need the AR from the merc helmet.
In the shoulder slots Might of the revenant and a Globe of clarity are the best choice.
For the back armor slot a Robust Backpack gives you the best dmg output, followed by the Spirit shroud of the artillery.
Arul sabas and rings depend on what weapon setup you are using. If you use fists only, go for two melee dmg bracers. With one weapon + fist mix one energy dmg bracer with one melee bracer and for dual weapon + fist go for two energy dmg ones.
If you don't need the AR, you can also swap the Merc gloves for Electrophoridae gloves for more +energy dmg.
Another nice thing to get a little MA boost is the Ring of crawling ants you get from the Jack Legchopper quest. It might be just the thing you need to get above 2k MA skill and the STA buff is nice as well.