It shouldn't be too hard to up the output to 550hp - with proper fuel and boost upgrades.
According to Chicane Tuning.
http://www.chicanesport.com/
RE:
http://www.saleenracing.com/page3.html
Trap speeds
Magazine numbers
Model 1/4 mi times 0-60mph
S351 12.7sec/122mph 4.6sec
1st year of S/C:
Can't help ya.