4800' elevation is a *****...what's the typical DA when you run? Also take into consideration an '04 GT likely weighs about a solid 400lbs more than your Valiant (if not possibly more). 14.05 in a stock '04 GT ain't terribly bad-especially with the elevation. Slicks&skinnies, 4.10s or 4.30s, ditch the sway bars, launch at 5k, shift at 5700-5800, drive it like it owes you money, you might drop into the mid 13s or better. Seen it...