Hey, this is a courtesy post for a friend, so please be nice
As a college student in a dorm my friend wants to step up from his tiny sat-sub PC speakers into a fuller and more bass driven system. The emphasis is on the bass, he loves my logitech z5500 sub (10" ported, should tell you something

) and always wants more. I told him he should probably save up his money and get an SVS, but he wasn't too sure.
Anyway, we need to find:
a) a simple receiver, probably a Yamaha or Denon off ebay (he buys lots of stuff off ebay)
b) A pair of good, cheap two-way speakers
c) A powerful subwoofer that won't disappoint
budget: $250-$300
DIY isn't out of the picture, but only if it would be totally worth it.
Thanks!