Couple questions about my Asus Maximus VI Formula MoBo

Hello! I have a Maximus VI Formula and I had a few questions about it.

1) Is the m.2 slot worth using for my OS instead of my HyperX SSD or will there not be enough of a speed difference to make it worth spending the money on? Also if it is worth using what M.2 drive would you guys suggest that has a good price to performace ratio?

2) Im planning on using the crosschill VRM watercooling block that comes on this board (Yes Im aware of the dangers of using a nickle plated aluminum block in my loop so no hating on that plz) but I saw that EK actually makes a VRM/Southbridge watercooling block set for this motherboard. Now I it would be prefereable to have a staright nickle block for the VRM but is the SB block more of looks or will it really benefit from also being watercooled? Ive had problems with the VRMs overheating and causing throttling issues while overclocking in the past on other boards but I dont think Ive had any such issues with the southbridge.

I wouldn't worry about the southbridge.  I'm not sure what boards you've used in the past but ROG board's VRM design is no joke.  Even without the water the heatsink should keep the VRMs nice and cool.  I remember asus or ROG putting out an article addressing the issues with the nickle, but I couldn't find the article.  I also couldn't find any recorded instances of it actually causing issue with that board.  So I'd say you're good to go man.  As for the m.2 I can't really say, a few google searches said it was a lot of work and really just about the same as an SSD, so personally I'd save the trouble and use the slot for the wifi module.