In my Buckshot X3 mid engine with a Jerico 4 speed, the Winters QC didn't last at all. The Speedway Engineering QC held up pretty well with a mild supercharged LS. I changed that to a 425 twin turbo and I immediately went through 2-3 Speedway units. The gears never failed- it seemed like the pinion climbed the ring gear and the case just exploded. We added gussets and braces, but the case continued to fail in the exact same spot. Again, I never had a gear failure. I installed the quick change unit from B&J Engineering and haven't looked back. The housing is much stronger, has webbing throughout, and has the same 10.5" ring gear as the Speedway QC. I added external bracing and added more mounting points to the frame just in case, and have had zero issues! B&J Engineering is located in Arizona, they pick-up the phone when you call, the answer emails in a timely manner, they have parts readily available, and they are sand sport enthusiasts. The B&J unit is also narrower than the Speedway unit which allowed me to install longer axles, thus decreasing CV angle and increasing wheel travel. And the ability to easily change the final drive ratio with relatively inexpensive quick change spur gears is itself a benefit over the Currie unit.
Just my opinion, but I went through this exact same hassle too many times not to share my experiences. Contact me if I can be of any help: Andy 858-449-9964