This may sound like a silly question, I am quite new to this tuning stuff. I am running the 89 torque & want to change it & try the 89 performance one. Do I have to return it to stock then install the 89 performance tune? Same goes when I want to install my 91 torque tune...return to stock first(after I fill her with 91 octane)? Thanks in advance.

Rick

 

Nah...methinks you just hook up the SCT X-Cal, program car w/ new custom tune, no need to reload stock

But I sure don't know what I'm talking about much of the time

 

he's right, just hook up the tuner and load the new tune...it will erase the old tune first automatically and then load the new tune