Either 325 or 330HP. It's mostly from a different air intake setup and tuning. It's still a N/A 4.6L 3V engine the same as the average Mustang GT. The rental versions are automatic only and traction control permanently on. For 2008, Hertz only has Shelby GT convertibles, no more hardtops.
You can buy a Shelby GT from ford. If you do that, you can get a 5-spd and fuctioning t/c.
It's basiucally a Ford Mustang GT with appearance mods and 30more HP