I have a PYR Chip in my PR3. It has no RPM limit, which is my only problem with it. You can get it with an RPM limit. I ended up installing a MSD 3 step rpm limiter, so i dont have to worry anymore. couldnt really tell a difference, because my stock computer was cutting out at 6800-7000(stock PR4 LS ecu), and then I could take it out to 7500-8000.
Im guessing ur thinking of the more common obd0 pr3.