RE: OS 28xz or LRP zr.32
Either you got the OS 28 for a killer price, or you WAY overpaid for the LRP...
For what you say you want to do in a Savage, the LRP is the only one that will fit. It will also do everything you want - wheelie, fast, easy to tune, etc..
The OS is by all accounts a monster of an engine though - would love to try one in truggy.. It's bumpstart only though, so can't be run in an MT.. Hell, if you got it for that good a price, get a used truggy roller for it...