Hey, whats up, I just got 4.10's installed in my 01 Cobra, I've had no problems so far, other than a tiny bit of gear whine. But I did buy the billetflow IRS Brace which cost $150, powder coated red, and I already had the Differential Brace (stock piece on an 03/04) installed before. Funny, I guess you could almost call both pieces the same thing, I've heard the differential brace referred to as the IRS brace and vice versa, anywho...go to billetflow.com, and the IRS brace on there is HIGHLY suggested if you're going to install 4.10's. the differential brace/irs brace (whatever you want to call it) is a stock piece on 03/04 cobras that you can buy from various places for rather cheap and goes nicely with new IRS Bushings and Differential Bushings. All this crap and I still have wheel hop. As for the drive shaft, I've heard you can buy the FRPP Aluminum Driveshaft, and have it shortened exactly 1 inch, and rebalanced for close to $75, haven't done that myself, but just what I've heard.