Originally Posted by theaudir8fan

Ok, I must admit that i was wrong on saying that bigger injectors will use more fuel, since the tune does determine everything. I think i meant to say that it has the potential to be more fuel consuming.

To OP, i think you should call forged performance to ask what fuel pump they are running. I think a 255 should be fine with 6 725cc, but it is probably pushing the 255 to max, 300 should be enough for 850cc. As for the drive shaft, i don't think it is a must, again talk to either forged performance or GTM about this. Most likely, the car is fine without it.