My word the AK5-C with Coyote, Laser/light combo, Angled foregrip and Suppressor is good!!!.
On the discussion of PDW's/SMG's not being suited for Engineer use. I completely disagree. The idea is that engineers are supposed to be using (or atleast supporting vehicles). Hence the best weapon (In theory) would be a SMG. Why, Because when being a engineer the majority of your gunfights centre around your vehicle, Either when repairing or jumping out to kill a enemy getting to close to comfort. Your hardly going to need to jump out of your vehicle to hit a 200m kill. I dont argue with Carbines still being the better choice though. Its just that in theory SMGs would be the suited weapon for the engineer role but because the Carbines are so versatile at all ranges they are the smarter choice.