I saw a post regarding this throttle body. I believe i have a 58mm one and no computer progamming, I have been through three tranny rebuild in 7 months and currently i am having problems and I dont know if it is opti-spark or tranny, or flywheel problem now. I took it to a racing shop and tested the car at WOT throttle while driving and a check engine light came up, check the code IT WAS TPS error, replaced TPS, tried it again TPS again. Tranny goes into safe-mode said the mechanic, this is where the 4l60-e allows you to go straight into third gear, so you can go home, i didnt know that. After reading the post in the engine performance I belive that this is the place to ask.