I'm one of you now.

Congrats...I read the other post and it looks to be stock except for aftermarket mufflers. It will not feel as torqey down low like your GT, but rev it out to 6800 RPM's and you will see the difference easily.

As far as the PCM being reprogrammed...no big deal. First thing you should do though is get some gears. 4.10 or 4.30's. Night and day difference over the stock 3.27's. As for the "vibe"...when you get your gears installed, get an aluminum drive shaft and you will be set. At this point get a chip too; they will adjust the speedo and can dyno tune the car slightly.

Also, if it doesn't already have it...get an aftermarket shifter. Pro5.0 or Tri-ax.

Enjoy!!

You got the vibe huh, most take it to the dealer they change a few things, then it is off to a Aluminum Driveshaft that takes it away, but I would suggest not telling them that you get a shimmy at 100+. They may not like that.

How are your tires? Have they been balanced lately? Are they worn, especially the rears?

I ask these questions because of the tires on my '03 Cobra. I cranked it up over the century mark and got a terrible vibration, which never happened before. It turned out that the rear tires were pretty much shot after just 15,000 miles. My '99 never had such a problem.

Either way that is my thought. I had my '03 up to 135 when the tires were good and it was like riding on glass, so that is where I would look.

Good luck.