Stat points does not make so much sense than in PL. In PL you can really see the big difference between full str bear and full int bear. In sl no one notices if you are full str com or full int com if you hide your attributes. But best for eng is full int. And dex for op and str for com. Full str eng has like 2 dodge more and lower dps. Eng damage is already low so full int is best. Also you heal more if full int. Idk about full dex, maby you have like 2 crit more or something. Damage is about same at full dex and full int. But if you dont PvP and you are 45-46 eng, i would say best is if you can get full int, damage implant and epic gear. Pink gauntlets are best. If you like napalm, then choose fused napalm because you can get close to 900 health and you wont die too fast. If you do PvP then plat dodge implant is best. And in long fights with coms use pink implant so you wont run out of mana and die because of that.
If you have any more guestions about engineers, ask me. I know like everything about this class. Other guy who knows as much is Mitchturbo or Akfury