WELCOME the G80 is not your tranny it's the locker in your rear axle differential, look on the inside of your glovebox door there is a sticker with a bunch of codes on it if you find G80 on that list then your tb already has it, it locks your rear axle if one tire starts to spin faster than the other,I think it's something like 200 rpm differnce(someone correct me if I'm wrong). If you don't see G80 then you have limited slip which sucks, it's like whatever tire loses traction gets all the power.
As for everthing else, check out the vendors on this site they sell almost all the stuff you mentioned or can point you in the right direction and just read the threads, it's all in there somewhere.
Have Fun
