What gear?

Somebody already mentioned the gear calculator...
Unless you want to swap center sections just for the occasional trip to the track (seems to be a bit much to me), How about a set 14" wheels for the back. You're running some kind of DOT tire now, right? Mickey Thompson has a set of 235/60-14s, that are 25" diameter, and I'm sure sticky enough. That's fully lowering your gearing by more than 10%, bringing your rollout from almost 88" to 78 1/2". IIRC, your gearing will be real close to 3.91 w/28" tire, with less mass to get moving!
Me, I'm kinda lazy, I'd rather just swap my wheels and tires.
(although at some point my quest for quick will lead to bigger #'s than my 3.55s)

Again, just another opinion,
Tom