Hello SirJet! The best thing you can do as an Eng/Negh'var is heal! If you're going for damage in PvP I'd say the Vorcha refit is the way to go. Negh'var still turns too slow to make good use of heavy cannons. I'll give you my setup I use on the Negh'var.
Tac team 1, Attack pattern Delta 1
Power to shields 1, Power to shields 2, Eng team 3, Extend shields 3
Power to weapons 1, Aux to Damp 1, Aux to SIF 2
Power to weapons 1
Hazard emitter 1, Transfer shields 2
Consoles I like are
2x armor, 2x sif generators, which increase Eng team and Miracle worker
Borg console, Field generator
3x whatever energy type you use.
I also use borg deflector, engine and honor guard shield.
Weapons for pvp, I'd say 1 or 2 beam banks and the rest beam arrays. Weapon type, phasers have a nice proc, as do disruptors, anything works really, just stay away from plasma.
Doffs, for this setup I use the Eng team cool down ones, forget the name, that way I can chain the one copy. Aux to Damp is good if the enemy team has a lot of tricobalts or shockwaves, so you can keep your Extend going.
That's all for PvP of course, STFs you can get away with heavy cannons and rapid fire. Also if you are healing in pvp, give your eps transfer to a tac bop/raptor. They will love it.
Here's a link to a good thread talking about other setups for the Negh'var and other cruisers in general. the page has the Negh'var on it, page before is a vorcha.
http://forums.startrekonline.com/sho...249906&page=10