if its a matter of speed, think about the reason those 600s and late 80s 650 Polaris' were fast. 2 main things- weight-suspension. My old 650 that was ported and had a set of PSI Stage II pipes ran 117 on radar. Not bad for a little 650. The advancements have been in both categorys, engine and chassis/suspension. Imagine how fast an apex would be if it had a SRX Pro-Action in it? Id be willing to bet 5-10 MPH real speed at least. Just a thought...BBY