well i played with my buddies LS1 (stall, cat back, lid and some other small things) last year i walked all over him by like 4-5 car lengths not spraying and with a slipping trans. well we played a couple times this year, nothing on our setups changed except i have a built tranny and a bigger stall (3600 9 inch vigilante) but while it was at the tranny shop (for 3 damn months) the battery was un hooked, it has a madz28 tune on it, i have the email tune from them and i have the tune on my laptop, but ive never had to mess with it before, i dont want to try and retune the car and get in over my head, i dont even know exactly which file it is (i bought the car with the laptop and the tune) so is it a possability the computer lost the tune?

 

If for some reason the PCM lost its flash memory, the car would not run at all or would not run very well, not sure if they have a "limp" mode that can't be programmed or not like the older ECMs where if the programmable part fails, theres some minimal parms that are permanent that the PCM uses to "limp home" so the car still runs to get you home.
Are you sure your car is running slower? Any time slips or dyno # to prove that theory to yourself. Are you sure your buddy didn't add a bottle without telling you and thats why your not pulling away? Or driver differences, maybe he learned to drive a little better.
I had a friend add NOS to his Z28 without telling me cause I always beat him at the track..thing was at the time he was a 14 sec car mine was a low 13 the previous year...the next year when he challenged me to another race, I was now a low 12 car, his was now a high 12 and I still won, so he was still pissed that he lost after doing that.

 

nope he didnt do anything to his car. we store the cars at the same place and his went in before mine. plus i hang out with him almost everyday. the car is running pretty rough.