honestly I dunno anything about the mechanics, just what my brother in law told me. He's about as clueless as I am sometimes but I just know part numbers and stuff....after all, I paid for it. I BETTER know what model number I paid for. lol
and yeah, that's the number on the little square things on the outside of the boot.
regarding whether to try to make it fast vs. getting another bike, I have seen non current CR125s, brand new in the crate for as low as $3000! Compared to a new YZ etc., that leaves you with a lot of spare change to spend on aftermarket. And it's a way sweet handling bike compared to the competition, in my opinion.