On an IQ cart there are 3 stock speed codes 1~3 code 3 gets you about 14.6 mph. There is one private code, code 4 which get you about 19.6 mph.
There are 3 ways to get code 4 speed
1 club car
2 speedylink
3 two speed kit @ ( gaminde.net )
you have options they will all give you about 19.6 mph speed
oh and the last one is made in the USA