Your rear end will be fine. Might want to freshin up the clutch packs though. 8.8's are pretty tough in stock form and can be made bullet proof easily. You t5 on the other hand is a different story. Your best bet for longevity would be use a clutch that will slip some to keep all the abuse off the tranny. And stay off slicks and hard launches....OH!!! And make clear precise shifts to ensure you don't miss a gear powershifting...t5's don't like going 1-2-1..oops @ wot.
I did have my rearend looked over when I had 3.73s installed they put in new clutches. I hope i dont blow my t5 up now. The only reason i ask this is i might get a complete supercharger for 500 from some family.
Go for it, thats one heck of a deal, even if its an old school supercharger. I wouldnt worry about your rear end at all, your tranny should be fine. I would be more worried about getting enough fuel and getting a good tune to protect your motor.
I made 475 to the wheels with my 331/ Paxton on stock axles, carrier, wheels studs etc. and about 200passes at the track launching at 4500 with the T5 until it grenaded. rearend held up fine.