I just recently installed a kenwood KDC-BT945U HU (50W peak x 4), polk audio db571's (75w rms) in the doors, db691's (100w rms) in the rear deck of my mercury grand marquis.
My old car (also a MGM) has some wal-mart special pioneer speakers in similar dimensions but an older less featured kenwood HU, KDC-X692.
It seems the polks need more power than the pioneers as I can not sustain 70% volume out of the head unit before the volume output drops dramatically. If I turn the HU down for about 30 seconds, then turn it back up, it's fine for a few minutes and drops output volume again. This happens around volume #24 (out of a 1-35 range).
At volume 23 the speakers sound fantastic and pound pretty hard for not running a sub.
If this theory doesn't sound right, please let me know why.
With that in mind, I think in order to not burn up my HU, I need to get a 4-channel amp to run the speakers. It's been 15+ years since I bought an amp for a car (college), but I always favored kenwood head units in cars and polk speakers in my house, so I figured both in my car would suit me well.
Just thought I'd ask what's out there these days that is relatively economical/reliable that will run these speakers.
Any info would be appreciated.