The best thing i can tell you is don't buy anything before doing some searching first. A lot of people new to the game buy things that look bright and flashy instead of things that are actually good products.
One thing that comes to mind if you are willing to spend a little bit more you could get a Sound Splinter Rl-p 15"
http://soundsplinter.com/rlp_premium_series_12_and_15_inch_subwoofer.html
They arent SPL subwoofers but they do get loud and sound good while doing it and a good price.
http://www.low-hz.com/commerce/catalog/index.php?cPath=23_24
Might want to check out the BM series-The Mag is one of the best all around subwoofers out on the market many will say and the BM is it's little brother
http://www.audioque.com/aq/SD2_5_Series.htm
Good company with good products...not sure what the price is on these though
https://ssl.perfora.net/www.ficaraudio.com/sess/utn;jsessionid=1545c40f8853659/shopdata/0020_Q/product_overview.shopscript
Newest thing that everyone is all about is FI built by experienced people
Just read on the forum every once a while and you will figure it out
One thing that comes to mind if you are willing to spend a little bit more you could get a Sound Splinter Rl-p 15"
http://soundsplinter.com/rlp_premium_series_12_and_15_inch_subwoofer.html
They arent SPL subwoofers but they do get loud and sound good while doing it and a good price.
http://www.low-hz.com/commerce/catalog/index.php?cPath=23_24
Might want to check out the BM series-The Mag is one of the best all around subwoofers out on the market many will say and the BM is it's little brother
http://www.audioque.com/aq/SD2_5_Series.htm
Good company with good products...not sure what the price is on these though
https://ssl.perfora.net/www.ficaraudio.com/sess/utn;jsessionid=1545c40f8853659/shopdata/0020_Q/product_overview.shopscript
Newest thing that everyone is all about is FI built by experienced people
Just read on the forum every once a while and you will figure it out