Outlaw M-200 sv. Hafler XL-280 bridged

Outlaw is a chinese product? Surely you jest.

Problem I see is running the 4 ohm speaker with a bridged amp such as the Hafler. Tha amp will effectively see a 2 ohm load in this case I believe.

Although I'm no fan of Chinese products the Outlaw is a mono amp and henceforth should be able to run your 4 ohm speaker and it will probably sound better only for the reason that the Outlaw amp is desiged for this purpose.Where bridging a stereo is merely a side benefit,not it's sole purpose.

the speakers are the WTMW HT Guide DIY. They are 4ohms. I get to 0db MV at times.
I built three for a LCR combination.I Will need three amps

It all depends on how each amp responds to the load intended.
The difference between 300 watts and 400 watts in nearly unhearable. Is this intended for center channel or sub duty? Are you going to redline it frequently?