I got a 2004 STX-12F and my cousin has a 2003 Honda three seater turbo off the line i got him because he cavitates like crazy but top end he has me by about 3 MPH, what would be the best mods for me to do, to gain that 3 MPH.

Here are a couple of mods to start with that should help you pick up some top speed.

Solas 12/18 OR 13/19 Concord Impeller. The 12/18 is a good all around impeller. The 13/19 will give you a little more on top (which means you will lose a little acceleration). Keep in mind that if you like to do a lot of starting and stopping as well as hard turning under power the 13/19 will put more of a strain on the motor. We don't recommend this. Even though 4-strokes have more torque that doesn't mean they can be subjected to more abuse without causing problems!

For the intake grate and ride plate there are a couple of ways you can go. You can use your stock intake with R&D's Standard Ride Plate (part# 121-12000). You will see improved top speed, but hook-up might be an issue. If you ride in rough conditions mostly I suggest going with R&D's Standard Intake Grate (part# 111-15001) and ride plate part# 121-12001 (designed to work with their intake grates).

If you plan to retain your reverse capability you will need to order the special bracket (part# 121-15011) to work with R&D's ride plates in order to do so.