This one is easy. Get another GS112 for not only money reasons, but for "sound" and versatility reasons. Adding a 212 to play with your 112 (8 ohms each) would result in mismatched power distribution.
I can see going with a pair of 212's, if you're one of those guys who needs HUGE sound but I sure don't, even on some of the bigger stages that I've played. I also prefer 2 x 112's in case one blows. Easier to carry too, plus you have what is essentially an extra baffle between the woofers, eliminating that distortion that can occur in multi-driver cabs (without a baffle).
Last edited by jeff7bass : 09-10-2013 at 10:12 PM.