Well, the reason I see a broken diff. being better than new axles, is that I've been itching for a Kaaz any way, but in this case, you're right, it's worse.

Acura will fix your hub bearings regardless of engine mods, I've had it done on mine, and they know mine is no where near stock. It's a safety issue that they won't mess around with. If they do give you any hard time, just point out that the wheel could fall off at any time causing an expensive lawsuit. unless you've done a big brake upgrade, there is no reason they have to deny you. more than likely, they may not even open your hood to check it out.

As far as taking it someplace to get it fixed, I know it's a bitch, but I'd do it yourself, that sort of stuff is really expensive. Though the bearings you can't do your self any way, that at most should cost you about 3 bills. As far new axles, you can get em' from discount auto with cores for like 160 bucks I think, though I'm not sure about that one. As far as diff goes, I dont know about other mechanics, but I know Acura charges 400 to r&r teh tranny, another 300-500 to crack the tranny open, and what ever the price of the diff. is. You're looking at at least a grand if it's a diff. If you do it your self, you'll probably save anywhere between 400-800 bucks in labor, and other than a normal socket set, the only specialty tools that you need is a 32mm socket for the axle nuts, and a snap ring pliers to remove the bell housing. After that, other than being really heavy, the diff just pulls out, be careful with the main shaft when you pull it out, and remember where everything went if you pull any of it out!!!

Good luck, if you need a step by step, let me know...

Later,
Aj