Z6 and Y8 trans diffs

[Cheetah]

Whats the difference in performance between a z6 and a y8 trans?

I would like to use a y8 trans but they are expensive. Maybe a y7 would be easiler to get a hold of.

[Toddnos]

y7 trannys suck.......well unless you have a turbo. the gears are too long
you will fall waaaaaay out of vtec each shift.