I have one of each maybe. 02 iq dealer upgraded to run 19.6 with the 22 in. tires it will run 22 mph. My 90 i converted to 48 volt, 48 volt solenoid, new charger, still running 36 volt motor. still on resistors, runs 22mph. The iq cart is really a smooth running cart, the 90 has all kinds of low end torque and throws gravel, a lot of fun to drive. It also is lifted and runs 22in. tires.This winter i plan on putting a controller and a pot box in it, but so far it is still running strong. I guess if it ain,t broke don,t fix it. I will have to get with Cerb Or Bama Wells to to find out how to wire it up though.