well these are the ones that i am looking at but they al basicly say the same thing but which one would be better to stack with drive/rpm
High Voltage Body Octane
Incarnate
Carnage
IntraXcell
Well, Incarnate is BA + Cissus, so it could potentially help strengthen your tendants/ligaments. Have you ever tried Cissus? If not, and you have joint problems, it is definitely worth looking into, though it's a bit more pricey than others.
IntraXCell was really the first popular BA capped product. It is equipped with ALA and NAC.
Carnage is the cheapest of the bunch (I believe the cheapest capped BA here). It is BA with a delivery system which, in a lot of users, buffers the annoying flush associated with BA usage.
All are great products. You can't go wrong with any of them. Honestly, I've used them all and haven't noticed a real difference between any of them. All will get the job done.
EDIT:
I missed Body Octane. It is definitely superior to all of the above. It is, IMO, the best endurance product on the market. Really unrivaled. Although it looks expensive, if you were to buy all the products in bulk you wouldn't save nearly ANY money at all, plus it wouldn't be flavored. If you're willing to spend the money, it's really a top notch product.