[cobradvm]

First off I should let you know I own a FFR, so now that that's out of the way, I would agree with the others that the F5 is the way to go with what you want. You can get the entire car built and painted with all new parts and done to an equivalent fit and finish of any of the other makes for probably $45 to $50k. You've already thrown out the idea of making it a clone of an original with the GT500 power plant. If you're good with leather and glass work, you're already ahead of the curve. The other stuff's not that hard. You could probably come out under $45k all in, depending on your paint skills. I chose to farm that part out to the tune of $8k, so you can probably do that part for a lot less.
The chassis is can stand up to anything you can throw at it - there are sub 10 second FFRs in the quarter mile, and F5 has it's own spec racing series - there's a lot of cars out there and the chassis has been well tested. The other benefit of building it yourself, is you can spread out some of the expense, by buying what you need as you go other than the initial buy in cost of the kit.

Good luck with whatever you decide.