I've researched a bunch but still am unclear about interchangeability between 06-13. Sellers on ebay have odd year ranges that I am not sure matter. Looking up diffs on Car-part is even more confusing.

My 05 makes 540hp at the crank and has the stock diff so I am on borrowed time. Its not a drag car, its a track car that I autocross and the street runflats don't stick at all so I think that helps.

Anyway. I have the 06+ T56 rear extension already so I am in the market for an 06+ 3.42 diff before I break my original and want to be sure of what is compatible. I know Z06 diffs have a larger output shaft so those are out unless I upgrade my trans (and for what I use it for and how the stock lived so long I don't feel I need the Z06 stuff).

Do all 06-13 non-z06 diff physically interchange? If so that means there are only two 3.42 options, cooled or not right?

Also, is there any other upgrade options other than going to 06+ stuff? I read about the C5 swap that doesn't require the trans ext swap and seems to live better due to the more compliant center mount instead of the c6 "ears" but considering I have the 06 case extension it wouldn't it make most sense to go with an 06+??

Also, any tricks to swapping the T56 rear extension? Or is it simply swap the internal parts (races etc) and bolt it up???