Are you data logging your runs? It will make you wince to see what the computer is doing. Im sure I'm making more power with my new mods because of the loss of traction over 5,000 rpm's in first and second. But because of traction loss the computer is pulling timing, closing the throttle body and shifting way before redline. Ugh. With the ET street radials I doubt your slipping, but the data logs will point you in the right direction as to why you slowed down. Perhaps your suffering knock retard throughout the rpm range? Does the computer need time to "adapt" to the new tune? Did the wife of girlfriend fill up with regular?

Les