Yes I agree you want it to be fast but responsive as well,when I hade the twins on mine it used to make 600 @ 1.3 bar and 650hp at 1.5 bar but to be fare they were maxed out at 1.5 as they were only the his ones but on the road response acceleration was brilliant I used it everyday for 15mths and never had an easy drive ,only thing that went wrong was I had to go from a twin to triple plate clutch ,if your car makes 680 plus should see you in the 10s no probs