RC10GT Speed
well first off the shorter the pipe the more top end you have. the stock pipe is all you need. its one of the best on the market. robison sells clutch bell up to 23 tooth i think. the shorter tires you put on are killing your top end. just remember the gt is a off road truck and not a sedan. top end on a truck is only like 40mph. that is real fast in a truck. no they dont make a 2speed for the truck. you wouldnt be able to handle it any way. the suspention cant handle high speed. you can go with a nova-rossi motor and do wheelies all day long and have a top end of about 40 to 45 mph. you can also run 30% nitro to get more power. but the motor that comes with the truck isnt that fast. it runs good but a little slow. good luck