I currently have 4 6.5" Audiopipe subs in two fiberglass boxes in the trunk of my car that are running off of a 600w old school PPI amp. I was thinking about upgrading to a single 600w+ rms 8" sub and building a center console box for it, but I want to get some opinions on which sub to get. The choices right now are the DD 608, DC Audio M3-8D2, and the SKAR AUDIO ZVX-8. My budget for the sub is around $200, any personal experiences with these or any others?