Hi I'm thinking about getting the Polk RTi-4s but they're pushing my budget already. I'm a poor college student and since I'm mainly going to be listening to music in my smallish dorm room, would I really need a sub to go along with the RTi-4s? I haven't had a chance to listen to the Polks yet and I can't seem to find many reviews online. I was hoping someone else has heard them and can share their opinion. I'm also considering the Infinity Beta 10 and the Infinity Primus 150. How do the three compare?

I guess what I'm most concerned about is how low those three bookshelves can go. In general, do bookshelf speakers need a sub and how much of an improvement would a sub provide? Also, what's a good, inexpensive sub? I'm looking at the Polk PSW202 or PSW303 or Infinity PS8 but I'm interested in any sub under $200.

One last thing - I'm going to be living with roommates and even though I take good care of my possessions, I can't guarantee that my roommates will be that careful. How easy is it to blow out speakers and subs and what's the best way to protect them?

Thanks for any input.

- Steve