its been said to death about comparisons etc, but the other thing that blurs the lines are gearboxes. You could have the same car, same power etc, but with with a twin clutch, one with and auto and one with a manual, and all 3 will give you different figures. Iv followed a 996 C4S round a track, and that only pulled a yard or so on corner exit, down the straights, it was even. Got a friend that has a 997 C4S, and that is quicker, but not massively, its about the same pace as a 4.3 AM V8. I think if you had a 370, then you would get more out of it, with more potential than a 350, but as you have a 350, id go out with someone who has the setup and power you are looking at, and see if you think its enough and if its for you.