^^This is the most accurate of the responses you got here (+1 rep.) As mentioned before, any camshaft designed for the K20 will work with the Z3 head, but tuning is your problem. The Hondata re-flash has NOT been tested with after market cams, so you would be rolling the dice on that one. The TOV project Si is running I/H/E with IPS cams and a custom flash from Hondata. I contacted Doug to see if this flash is available for public consumption and I was told not at this time.