The guild I'm in has Kara more or less on farm and is pushing hard to develop the roster for Gruul's. Since Gruul's is more or less the 25-man extension of T4 content, I'm thinking that the gear/stat requirements would be relatively similar. Currently in self-buffed bear form, I have 13.5k health, 26.8k armor, 29% dodge, and 423 defense. I can possibly do a bit of re-gemming and up my health at the expense of a bit of dodge and defense, but other than that, there's very little from the already sparse feral tanking upgrades I could get out of Kara (Moroes trinket, T4 head, upgraded rep ring). I'm not counting badge gear upgrades because most of them would be 3+ weeks away if all I did was run Karazhan.
I'd offer an armory link but I hardly ever log out in bear form which means all you'd likely see is my hodge-podge of caster gear.
So based on those stats, do I still have some tweaking to do, or might I be adequately geared to get my foot in the door for Gruul's?