Send Resko1 of Experimental Audio Solutions a PM. Check out my sub he rebuilt for me:
http://www.caraudio.com/forums/subwoofers/505317-my-esa-built-3hp.html. His work is top notch, without a doubt.
There are a lot of subs out there which sound fantastic and can get plenty loud for all types of music. Matching brands does nothing what so ever; a sub and amp of the same brand will not magically sound better if they're paired up with each other. Yes, there are some companies that make amps and subs that are really good, but don't get into the mindset that matching them makes them even better. Also, before people start flaming you (it's bound to happen), just know that your installer is only that: an installer. His job is to push brands and make money, so take everything he says with a grain of salt. If you get past the trolls, you will not find a better place for information than this forum.
Good subs off the top of my head that are around the $200-$250 price point:
TC Sounds LMS-R
Sound Solutions Audio ICON
Sundown SA-12's
DC Sound Labs Level 4
There's plenty of stuff in the classifieds section as well, so don't be afraid to shop around there. There are some subs in there that will destroy anything that's around their price point, you just have to really do your homework and be patient with this stuff.