supposedly they have thicker ringlands, I had my stock z6 piston up to a vitara and couldnt tell a difference, but then again I didnt measure it so they could be thicker.

as far as rev'ing it up, with the lag monster turbo I got I need all the top end I can get, and it still pulls hard so I rev mine up to 8k, sometimes a little higher, d16z6, stock valves/springs/retainers, stock cam w/272 regrind from delta. I used to feel real bad reving it up that high but it still pulls and hasnt complained yet.

 

I was thinking of changing my springs, considering the low cost but I was told the retainers were not nessary. what about rods? crowders are very expensive but egl. are half the price are they still a good choice

 

tunertoys sells h-beam rods for about half the price of crowers. same as scat rods off ebay. check them out if you're on a budget