Equalizing an amplifier

Man, those cabinets are made big for a reason... and they don't want you to test out why... fuck that, build yourself a soundproof test chamber then, coz I'm sure as hell not buying anything until I've heard it cranked.
 
When I went up to brisbane for a day I popped into a music shop and they had a fairly large sound proof (maybe not 100%) area with full stacks and stuff. That was awesome. That's the only one I've seen though.

As for the amp thing, do you use any pedals at all? there's only so much you can do with an inexpensive amp's onboard distortion and EQ.