Darkside
Check out this webpage.
http://www.formula1-rc.com There are two articles on how to set up an F103. They kind of contradict each other, but they're written by two different people. They should give you some ideas about getting your car hooked and also how to adjust the tweak screws.
melvin
Kimbrough makes a 48 pitch 75T spurgear for F1 cars. It says on the package that it's for Cross and Tamiya F1 cars. Sorry, I don't have the part#, but your lhs should have them. Depending on the motor you're running and track layout, I'd go anywhere from 12T to 15T pinion. I run a P2K Pro with the 12/75 combo, but I don't need the top end. You should get around 10 min runtime with matched 2400's.