Is the 4000W rating RMS or peak?

It is peak. RMS ratings are 4 x 130W plus 300W at 4 ohms, 4 x 220W plus 600W at 2 ohms, and 900W on the sub channel at 1 ohm.

Can it run four speakers and a subwoofer together?

Yes. Four channels drive the front and rear speakers and the fifth drives the subwoofer, all from one amplifier.

The sub channel is stable down to 1 ohm, where it is rated 900W RMS. The main channels take 2 ohms stereo or 4 ohms bridged.

Bridged, the four main channels deliver 2 x 420W RMS at 4 ohms.

At 1-ohm sub loads and bridged output the amp draws high current, so plan on thick power wiring and a charging system that can keep up.

The amplifier itself; check the listing for the included mounting hardware and manual.

20 stores we checked sell it, including Robidoux, DB's Car Audio, Factory Direct Car Audio, Robidoux Inc. Distributing, Livewire Audio.

At Robidoux Inc. Distributing, for $245.00, 39% under what the other stores charge, as of our latest check.

$245.00at Robidoux Inc. DistributingChecked 7 h ago

39% under what the other stores charge

Compared across 20 stores. Prices are checked against each store and labelled with when.

It checks today's price at every store, compares the alternatives and answers in about a minute.