how about this
http://www.hsuresearch.com/products/stf-1.html
am not sure how good it is though...but its in the price range and its HSU
...more importantly whats your room size? Bigger room then you need to spend more dough....and how old is your polk sub? in my opinion to get a good sub you would need to bump it at least to the 400-500$ mark. Spend once, and spend it well. Dont buy something inferior and then guess what before you know it you are back again for a new one! So save until you can get a good one...is how I am doing it. I got my towers & receiver...now sub...later center & surrounds
ps...But, dont take my word for it, i am new to this stuff.
http://www.hsuresearch.com/products/stf-1.html
am not sure how good it is though...but its in the price range and its HSU

...more importantly whats your room size? Bigger room then you need to spend more dough....and how old is your polk sub? in my opinion to get a good sub you would need to bump it at least to the 400-500$ mark. Spend once, and spend it well. Dont buy something inferior and then guess what before you know it you are back again for a new one! So save until you can get a good one...is how I am doing it. I got my towers & receiver...now sub...later center & surrounds

ps...But, dont take my word for it, i am new to this stuff.