Get ready to do a HUGE amount of re-engineering. I've done the frame-narrowing thing on a few round track race cars, and it's never as simple as a bull session around a case of beer makes it sound. You'll encounter major changes in steering geometry caused by changing roll centers and Ackerman angle changes affecting the toe-out in turns. You'll end up with a pretty good straight-line machine that will have totally unpredictable handling in turns. You'll also have to completely redesign the motor mount system.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!