I bought a car with a freshly built bottom end (86.5 wiseco pistons / .020 over bore, H Beam rods/arp bolts, ARP head studs, etc), S2 cams & springs, Comp stage 3 clutch, GT35R turbo, tubular manifold w/ dual wastegate, open dump, Walbro 450, ID1300X, FF sensor, etc. The car is obviously capable of 600+ HP (injectors might be a bottleneck?). However, the tuner has stated that I should stop ramping up the tune at 500. I see a lot of folks with very similar builds running 600+ HP tunes. Is reliability at these horsepower levels mostly a factor of tune quality, maintenance, and aggressiveness of driving? Or are sleeves likely to expand or crack above 500HP regardless of managing these variables? I guess I already know the answer, but I am a little disappointed since my car has unneeded mods if I’m going to stay at 500 or less. For example, I don’t think cams, springs, GT35R, or stage 3 clutch are needed. The clutch is especially annoying. Seems stage 2 would be a better option at that power.

 

I don't really think there is a straight answer to your question. There are many factors that come into play. Like intended usage, fuel type, engine tolerances etc etc all things that need to be factored in. Take what you read online with a grain of salt. What works for a pull or two on a dyno doesn't necessarily work out in the real world. I would trust your tuner to steer you in the right direction based on the goals you have communicated with him/her.