Chris a new body would be cool
How about this from Kamtec?
Or a carbon look VW Scirocco?
Or how about this speedy little Honda?
Finally, if you want to keep to the Shamcar tradition how about a Focus powered by DB Ultimatum fuel, and a sump full of Control oil:
Seriously....
DP ULTIMATUM!?!?!??! 
PS: I can't find my Initial D shell anymore
The other cheap AE86 shells suffer from terrible shamness