I am not sure on the GMPP but the stock tune can benefit by increasing to 95-98 octane maybe more with a GMPP kit. I would not run straight race gas but 50/50 and at least 50 miles before you run the 1/4 maybe of some benefit. Remember don't run with a full tank adds a lot of weight. Our stock ECM's run with a bit of retard all the time so the extra octane may allow a bit more advance without knock, if you look at dyno sheet after the engine gets into boost you can see it retard the timing as boost increases. The 1/4 is one of the few places this will add benefit if done right. On the street you are just wasting money.
It won't make you go blind
Your face won't freeze that way
You won't be stuck using race gas all the time
It won't hurt your car, unless you put in leaded, a lot of race gas is leaded.
You will want to run it all the time, the car will like it.