I stepped up and replaced my 70 watt per channel Alpine amp with an Alpine PDX4.150 unit. I was worried it might be too much power, but you guys said no problem. The sound difference is phenomenal, deep mid bass response, and a real sense of clarity. The change in the soundstage is striking! The Sr6500's eat the power up, and I have not had a problem with the rear MMC's pulling the sound away. I am using a front bias with time delays. Some of the XM sound effects they play during the day can startle! I love the sound, I have always wanted good crisp clean sound, I find that I can for the most part leave my EQ flat across the board. The speaks need that power! I buttoned every thing up with a good cable routing, and a nice main breaker 1/0 cable feed to the rear with a nice fused distro block to feed #4 wires to the amps. The grounds were bonded to the car with a multi stainless steel screw plate that was undercoated over top and bottom. I sure enjoyed this project and have been rewarded with clean power and the sweetness that comes with 30 to 40 hours of breaking in the SR's.