Gears. 4.10 minimum. The RPM difference between the 3.73 and the 4.10's is minimal but the acceleration difference (SOTP) is much better with 4.10's in my opinion.
Mind if I ask, do you have a stick or automatic ? I only ask because its going to affect the decision of what we tell you.
If youre planning on staying n/a, I would go with 4.10s or 4.30's instead of 3.73's. Like Wickedgt70 above said, the rpm difference between the two ratios is minimal but 4.10s give better performance. If youre supercharging, Ide stick with 3.73's. Should you decide to get the gears, I recommend www.stangstore.com as the place to buy them from as they will be cheaper than most other places.
Sticky tires are a good idea and you will need them once you switch gears. That much I can assure you. I personally dislike the idea of the throttle body. Its been shown MANY times that no real power gains are offered with a larger throttle body vs. the stock one.