Im going to look into pinion shims today and the auto parts store in town.. thanks!

as for a tuner? nah man, that sct stuff is sooo expensive. If I could get a tune for around $200-$250 i wouldnt be so afraid of buying it. I mean the benefits are crazy i could mess with shift pressure, comp codes, tires, gear ratios, etc. Just too damn expensive for me right now.

YOu do know that your speedo will be off. ANd if you search around you can get used tuners for pretty cheap so you can fix that speedo and gain a few poines too :)

And for the speedo if your 99-07 you have to get a tune. If your older then that you can change the speedo gear in the tranny or 94-98 can have a tune uploaded to change it also.

got them all installed and whatnot now, everything works perfect. first thing i did was floor it onto the main road and i almost died... haha. highway isn't that bad, even though 80mph (guessing lol) is going at 3000rpm... defiantly a MAJOR improvement over stock 3.11 or 3.23 (i forget)

lol you should really go easy on it for a while, let it break in for a few hundred miles before you get on it. i would lay off on it for a while.

there is no need for a breakin just get on them i got on mine once mine were installed and nothing happend

their used anyway, no break in. loving them to death!

As for the mechanical or computer controlled spedomoter here is your answer courtesy of AM.

"Mustangs after 1999 use computer controlled gauges and can be calibrated with the tunes for gear and odd tire size changes. Pre-1999 Mustangs use a mechanical speedometer so the car's computer has no control over the speed reading. A rotating cable runs from the Mustang transmission into the back of the speedometer. The tuners can not be used to calibrate for gear changes on these cars. You can however calibrate for gear changes by replacing the speedometer driver gear at the transmission end of the cable. They are available from most transmission shops, or online at http://www.steeda.com or http://www.50resto.com for about $10-20 and are color coded (for the Mustang transmission type and gear ratio) and are easy to replace."