I don't personally have heated grips. So far, I have ridden from 28 degrees down to 3 degrees. No matter what, my finger tips get cold on the trail. Luckily, we don't have to endure much of that here. When off trail, we are generally riding hard enough that being cold is not an issue. Most times, it is the opposite. I will sweat and get my gloves wet from inside out. Just be prepared and have a few extra gloves in your pack.
One of the biggest things I miss about the sled is having a spot to dry/warm gloves and goggles. A few seconds in front of the muffler us usually enough to defrost my digits, but has also warped a goggle lens or two. Still trying to get that sorted out...
I wear lighter gloves that range from 40 grams to 100 grams of Thinsulate. I prefer to have good feeling on the grips and levers over superior warmth. Then I also pack a pair of 200g gloves and a few liners for that inevitable frigid ride back to the pickup.
I have a Moto Trax Enduro on a 2015 WR 450. I didn't do anything fancy for the intake. Simply installed some pre-filter material on all of the openings of the air box and then put some pre-filter material over a dry foam filter. Haven't had an issue yet.
Also installed a Thermo-bob. Seems essential for these snow bikes to run correctly. Made my own engine cover for the left side out of heavy canvas that seems to really help. Put some pre-filter material over the radiator shrouds to prevent ice build up. Changed oil to 0-W20.
Fill it with gas and rip...
Very happy with my set up and am having a blast.
Good luck, have fun, and be safe!!!
Dan