You may actually find its not the software but your computer that cant handle the HD. You could try other editing software, such as premier pro, or avid, or if your on mac try final cut.
Short back ends make it feel lighter and flicky, i run a fly tiarra with i love, i would recommend fly cranks also if u want lightness.
Go on www.thesourcebmx.com and look at all the stuff, has weight next to items.
Hope are one of the best companies in the world, buy the looks of it one of your pawls have come lose or you have stripped the teeth rings, they will sort it
have faith.