Local shop will be doing the whole rebuild for me, and they were not giving me prices on parts just telling me what to price out for parts and basicly hinting to me that I would buy the parts and bring them in for then to install is what I understood from the whole consultation.

 

Make sure you check with them on the parts list and ask about the warranty. If you don't buy the parts from them and it goes bad they can point at the parts and say they where defective. If you buy the parts from them there is no finger pointing. Its all on them.

 

I totally second this opinion,Auburn made the SLP upgraded diffs for the Camaros SS but they had to be ordered as an option.
I'm sure there's one that fits your car but best to let the shop doing the work order and install it IMHO. Just as Gorn said for the warranty and not being responsible if the wrong parts are ordered. You'll probably pay a bit of mark up on the parts but the piece of mind is well worth the price.

 

The axles can only be 26 or 28 spline and all fourth gens are 28 spline axles. The 27 splines you are referring to are for the yoke. There are two different carriers for our cars. Series 2 and series 3. Series 2 fits gears 3.08 and down (numerically) while series 3 fits gears 3.23 and up (numerically). That carrier I listed fits any gear that is a 3.23 or higher (numerically), so 3.42, 3.73, 4.10 etc.

Personally, I use the solid spacer every time. But that is just me. Like Gorn said, some shops will only want to use a crush sleeve and that's okay too. There is nothing wrong with that route. I just choose to use something that is easier and just as reliable.