Well, Stage 1 is up and running with the SPT.....throttle response is immediate and the car boosts sooner as well. I can notice a difference particularly in third (it pulls as hard as 2nd did before the flash!) so i would say it is all worth it. SPT sounds great still too.......i spoke with a few people in the business of tuning and they reccomend i run a Stage 1 91 octane mapping so my car doesn't run too lean with the aftermarket intake. I have a base 91 map and switch 93 realtime on when its go time. To help prevent any knock at all i run 93 octane through the car at all times. I swear it improves my gas mileage and performance enough to justify spending the extra couple of cents per gallon.