what does the computer control on a tpi unit and if i was gonna dump the tpi unit and go with a carb. what would i have t do with the wiring harnsses.

2. if i was goonna switch to an ls1 what would i have to do with the wiring harness

also witht the wiring harness for head lights and stuff does any of that stuff tie into the injection stuff example if i dumped the tpi or went to an ls1 would i need to completely rewire the car???