* Gear ratios: The specific gear ratios in the transmission will influence top speed.
* Tire size: Different tire sizes will affect the final drive ratio.
* Aerodynamics: Modifications affecting aerodynamics (e.g., spoilers, body kits) can slightly impact top speed.
* Road conditions: Headwind, incline, and overall road surface friction all play a role.
* Modifications: Engine modifications will significantly affect top speed.
While a stock 2009 Mustang GT might *reach* speeds in the neighborhood of 140-150 mph, this is not a guaranteed top speed. The car's electronic speed limiter is likely to cut in before reaching these speeds to prevent damage. Furthermore, attempting to achieve such speeds is dangerous and should only be done in a controlled and legal environment.
