I just wanted to know a little bit more about DD's 12's. Is it a SQ or SPL subs or both? would it be wise to buy the DD2012a which handles 300rms or the DD3512c which handles 800rms. I would only be putting 600watts x 2 ohms from my USX800D. How do these two subs rate to an Alpine Type R 12"? Any more info on this would help out a bunch. Thanks