What does 2000W RMS mean here?

It is the amplifier's continuous power rating into its rated subwoofer load. Peak or max numbers you see elsewhere are not the same figure. Match the subwoofer's RMS rating to it rather than its peak rating.

Will it fit a small install?

Class D amps run cooler and smaller than Class AB designs, and Stinger builds this one on a compact metal chassis. Measure your mounting space and check the terminal layout before buying.

Do I need to upgrade my electrical system?

At this power level, expect heavy-gauge power and ground wiring, a fuse sized for the amp, and often a battery or alternator upgrade. Stock wiring is usually not enough.

What is the remote bass controller for?

It lets you raise or lower subwoofer level from the driver's seat without touching the amp's gain settings. It adjusts bass output, not overall volume.

Can it power door speakers too?

No. It is a monoblock, meant for subwoofers. Door and component speakers need a separate multi-channel amplifier or head unit power.

What comes in the box?

The amplifier and its remote bass controller with cable are the core items. Check the listing for the mounting hardware and manual included with your unit.