Have a 99 Mustang vert daily driver with the Mach 460. I had a local stereo store add a sub and amp years ago. Not sure how it's set up though. Now, I just bought an Eclipse CD5423 and an adapter for the front speakers which will now fit a 5 1/4 and tweeter up by window. Thinking about putting either KAPPA PERFECT 5.1 or CDT Audio CL-51-560 5-1/4" What kind of amp should I get? How much power? Can I just leave the existing rear speakers or will they even work without the 460 head unit? Should I get a kick panel enclosure, don't want to spend too much money does it make that big of a difference? Less than $500 hopefully. Any suggestions?