Alright so heres my situation. I currently have 2 12"alpine type R's. They are dual 4ohms and i have them wired up at 1ohm on my mtx amp. My amp is a ta7801 which is advertised at 1200w rms at 1ohm. But the birth/dyno sheet with the amp is 1663rms. I am pretty happy with this setup but just like everone else, you always want something newer and louder. Well a buddy of mine just offered me 300 for just the subs and custom box i built. Considering i payed 115 a peice for the subs this really got me thinking. Well through a couple people i know and just seeing on the internet Fi audio makes some good stuff. So here is my real question and goals. What would be the best sub for me.(maybe not even an FI) I plan on sticking with my amp. So thats in the ballpark of around 1500watts rms realisticly. I think i have enough room for a 15". I plan on running one sub. custom enclosure of course. I dont really want to sacrific any sound quality and while being louder. Compared to the type R's. The type R's have done me good. I have my gain almost three quarters up and they are handling it good. But i just want to know what sub i should go with and if its worth it. Im guessing a 15" bl will be louder but will it still have comparable sound quality to the type r's? Will a btl be sacrificing to much sq? So what sub 12" or 15" will fit my goals of louder than 2 type r's and while having about as good sound quality. Thanks in advance Tom