Very good, Troy; the MRX500 should serve you well.

Using the "more gas in the tank" attempted analogy though, indicates that you may not be grasping the concept. A car doesn't run any better with ten gallons in the tank than with one. If the tank was completely empty, then there's a difference. If the amplifier in the receiver can supply enough voltage for the needed volume, there's no benefit in buying another unit with a higher voltage supply which would just sit there partly unused.

Enjoy the music, not the equipment.