[suicideneil]

13-16 tooth pinion will net you anywhere between about 40-50mph roughly, I wouldnt like to say the exact gearing you should run as that will depend on many things like the size of the track, your temps, ambient temps etc etc. I'd check into the buggy/truggy sub-forums and have a look at similar setups for a better idea; Im more of an MT guy than anything else. Run time is another good question, but 20-30 minutes is the norm, again- depends on a lot of things.