Only you can say if it's worth it. They are pricey but they are the one thing on my truck that I've pretty much built and forget about them. If you intend on running a high powered BL system then I think they are a must. There are some other options out there that are pretty good also but I can't speak for them. One things for sure, you don't want to be taking your diffs apart any more than you have too.
http://www.rc-monster.com/proddetail...diffset&cat=40
The 8's will be a little bit more but just e-mail Mike and he can get you a quote. Good luck.