Reply to Dirt Cheap PA Amplifiers

Okay so I've just got a new Saturday evening residency at a small venue, and it's PA system is a MESS. They've got an old NSM jukebox (one of the first CD ones, I believe it's a debadged Heritage) and a Blackbox-AV MPA150 amplifier, along with a bunch of Wharfedale Force 2180 speakers.

The setup is one of the most whack ones I've ever seen; 4 or 5 of the speakers are wired up to the jukebox, and another pair are wired up to one channel of the MPA150, and the other channel is driving a single speaker outdoors. It's not exactly the ideal setup, as the NSM keeps (I believe) going into protect mode which also stops it from outputting via RCA to the MPA150. The wiring is all mains cable (yep - wtf?) and there's wires not connected to anything as well.

Basically, it needs a complete re-believe and re-wire. Ideally, I'd like to add another PA amplifier to drive the main speakers and just use the MPA-150 to drive the outdoor speakers. So basically, here are the main questions:

1) Why the hell are modern PA amps rated so much higher than stuff from the 80s/90s? Is it literally just a case of manufacturers playing silly buggers with their rated specs, or are they ACTUALLY higher output?

2) Does anyone know of anywhere - aside from Gumtree and eBay - I can pick up something sub-