alright, theres SPL and theres SQ, spl is as loud as you can get, and sq is as good sounding as you can get... do you want either? or something inbetween? and how much do you want to spend?
What does a "few hundred" mean? $200? $400? What size sub? 10, 12, 15? What type of enclosure? Small sealed, large ported, bandpass, etc. Details make this a lot easier.