I'm going through the same dilema that you are, i have my A14turbo in my 1000 and after several snaped axels and diffs i want to re-do the rear end so that it copes with the extra power while keeping it light weight. The power output of an A14turbo wouldn't warrent using a big heavy diff, R31 and the like would be heavy and have a prefound effect on handling, espeically when used in a race car application.