I recently purchased both the MM651 and MM6501 for my Sony CDX-GT630UI head-unit. I have 2 12" subs that is powered by a 500W mono Kenwood amp. I haven't heard how the speakers sound yet. Should I get a 4 chan amp to power the speakers since they are 2.7 ohms or will the head-unit be sufficient amplification? I really want the most out of the speakers but I also don't want ear piercing treble. If it's advised to get an amp would this one be suffice? Thanks.