sportsman's advice

Lose the 3.55s (very easy to sell or trade) and get a set of 4.30s. That will eat up most of the grand if you buy a ring and pinion and bearings and have someone set it up. With the money left get some decent tires. Then you can start doing all the "sciencing out" and debugging to see how fast it will go. But with 3.55s you are giving up a lot of torque at the track. So I'd say get the gear, then get the tires. If you need to drive to the track, get a set of 14" wheels and the smallest diameter slicks you can find, and run them at the track. It will look a little stupid but they'll act like 4.10s.