HiC.d.OuT

What's up fellas Ive been trying to get into stunting for a few years but bought my bike new in 08 and just wasnt ready to *** it up...well the time has come had it for 5 yrs now had a few minor spills my last being on nov. when i tried to practice it went well ( 12 oclocked a few times on stock sprockets ) when on my last session I went down and cracked my clutch cover. I do have S.I. Cage bought it About 2 years back and used to lay the bike down a lot so I think the studs took their toll and cracked on me causing the cage slide up and hit the cover. Long Tory short I'm getting ready to fix her and install the 50t sprocket my S.i. Kit came with now I did my research but all my ?'s haven't been answered. I'm getting a front sprocket 16t stock thinking of 15t and a new chain but I don't know the number of links I should be getting. I've heard 120?!? Now I do want to be able to hit at least 100-120 mph will I be able to do this but not that big of a deal since I want to slow down this year. Ill be getting 15t front 50t rear 520 pitch with a 120 chain am I headed in the right direction?!? Any input will help and one more thing are there any guys from n.y. Here queens area that practice I ride with a club but they are not stunters lol and I really want to dedicate myself to this this year. Thnx again