Canyon Carver project?

I'm wanting to build up my space duster demon clone for the coming months and I want to take it to the track & strip on the weekends.
Now #1. I need it to be reliable, but I want it to be fast and not guzzle gas. I'm shooting for 25mpg.
#2 I live with fairly "unkept" roads. Anything on the road lower than 2.5" will be scraped to bits. But I still want my ride to handle well.
#3 I'm aiming for a manual swap but my budget for this endeavor is $4k.
-SD