I added 4.10's, then a week later the SCT tune, it really woke my 99 up!!!
99 GT--> SPRINGS, O/R X PIPE, COBRA R'S, KAENEN 5INCH COBRA R HOOD, MICKEY T'S OUT BACK, 4.10 FMS GEAR, SVT FUEL PUMP, SCT BAMA HANDHELD, 125 HIT OF JUICE.
79 NOTCH--> WORK IN PROGRESS, FLINSTONE DRIVETRAIN FOR NOW.
99 TAHOE--> DAILY DRIVER TO KEEP THE SHOES FRESH ON THE GT.
I say skip the tuner, skip the intake, skip the gears, and go for the rear suspension pieces. It don't matter how much power and torque you have if you can't get it to the ground.
Get with Sharad, he'll hook you up with some totally rad UPR rear suspension pieces. I love their stuff, I wish they did Mustang II front suspensions and anything for my GMC's suspension. (I had their full rear control arm set on my 2010 GT, totally changed the car from bad to rad!)
This would be a really good choice, if you're unable to get the gears locally through your friend.
The tuner is the most important part, though, so even if you only scoop that up, you'd still be getting the best performance. Of the mods you listed, the Tuner is going to be the best bang for your buck at this point. Then, down the line as you add more parts, you can use the tuner to compensate for them.
I say tuner all the way!
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