I grabbed the Metal kit, and on first pass it seems that AD2 is set up in 2 parts per kit. One is the kit pieces themselves, the other is the beats preloaded into them. The Metal kit pieces themselves are not extremely different from the other kits. I have not tested tweaking one kit to mimic another, but with all of the options it is most likely possible. The beats are a bit more aggressive (which can also be gotten from the MIDIpaks).
So... to get the highest versatility of sound on the initial offering I grabbed the Sonor Latino Bongos, Mandrinke Djembe and Sangban as the other 3 kit pieces. Of course, the very first thing I did is swapped all of the pieces in one Metal kit for these and ran some of the Metal beats on them. Now that was a rather interesting experiment... "Ethno-Metal"