I have the SLP intake kit and air intake sensor relocation kit on my 2015 M8000. I put the kit on when the sled was brand new so I don't have experience with the stock setup. However, I have yet to experience any bogs when I am in over the hood deep powder. The sled pulls great all the time.
I had their intake on my 2009 M8 as well and it worked great as well. The two extra intake vents under the hood are there for when your external vents get plugged with the snow your engine creates enough suction to open the flapper doors and allow the engine to breath.
I believe the air inlet temp sensor is moved into the air box in from to the throttle bodies to get a more accurate temp reading (I.E. Cold Air). This is done so the ECU can program the required fuel more accurately than having it read the under hood ambient temperature with the pipe and engine heat creating high temperature false reading and not the true temperature of the air heading into the air box.
All in all, it's a well thought out kit. Even better is throwing their single pipe kit on and loosing all that weight and gaining horsepower. The best part about that is they provide a pre-programmed Power Commander that is fine tuned for the application so you don't have to mess with trying to dial in the fuel controller. It's set perfectly from SLP. Also, I saved a bunch of money by switching to Geico
Just kidding I saved it by buying a Power Commander five (PCV) in the for sale area of this forum and SLP sent me an email file with their fuel program, which I uploaded into the PCV and all is well.
Sorry for the book but, I hope it helps.