Hi...I have a 06 IS350 and added to the factory system a Alpine PDX-1.600 amp 4080 box with a 12" sub back in 2008. The amp is now dead and have narrowed down the replacment amp between a Kicker 10ZX4001 amp or a Alpine MRP-M500. The speaker to be powered is a Kenwood KFC-W3011. The speaker peak is 1,200w / Max 800w / Rated 400W. It is a 4 ohm speaker. Any advice/opinions are greatly appreciated.

 

Whichever one is cheaper. Both will provide the power you want to drive your sub.

When it comes to a dedicated sub amp, my personal opinion is that brand matters little if at all. THD ratings are irrelevant since your are only reproducing sub bass/bass frequencies. Even amps with a 10% THD sound "pretty much" the same as those with .1% THD.

That being said, and before I get blasted by other audiophiles, I am basing this on the "general client" that comes to the shop and wants "MAD BASS YO!"

If you are using a ported (or worse - a bandpass) enclosure and are just looking for big bottom end then use whats cheaper.

If you are a sound purist and want the best sound possible out of those two then choose the lower THD @ 4ohms and put your sub in a sealed enclosure.