Please advise. I have a 2004 SVT TERMI and man is she a beautiful machine. I just ordered a full tilt boogie deluxe setup for the rear-end to include 373's ring and pinion. I'm not the mechanic. He has a late model "99" Mark VIII pumpkin and thought I could have it to build and "to keep my OE one in tact". Does the factory pumpkins 8.8's match identical or is their any reason I would not want to do this? Splines and all are factory on my TERMI. Please let me know before I make a wrong move here. Many thanks.