Alright, right now im running two Alpine X 10" and i guess there pretty loud and have great sound quality for what iv heard, but iv never been able to find the actual SPL rating on them so i cant really compare them to anything else i want to buy.  Basically, iv been thinking about buying new subs for a while now but im not too sure which ones to get.  I still want SQ but i want to be a bit louder ^^.  Im just looking for any input really, im quite new to this stuff and havent heard many other systems other than my friends 2 W7's. Any suggestions are welcome  -Thanks      Mike.