how about I say that if diving 30 degree water, I don't care what brand you buy you need to have good technique and adjust the regs. Plus, gas selection will affect breathing at that depth, regardless of temp. You are demanding answers to a question with not quite enough information. 37 is cold(ish) and a world different from 30 degree water IRL diving.
You also didn't discuss surface temp.. that plays a factor.
Now, I have done a LOT of actual cold water diving, and when worked for Mares a while back, lots of Long Island Sound diving. I would not hesitate to dive my regs (Deep 6 Signature) there to the very muddy bottom at any time of the year.
At the risk of losing a sale, if you have to ask the questions you did in the manner you did, I am honestly a bit worried that maybe the type of dive you asked about is beyond your knowledge, experience, trng etc. Not because you asked regarding a particular reg, but because your question didn't reflect knowledge of the variables for that type of diving.
It would be like demanding a race set up on a race car that does oval track for your mountain ride to a mechanic. The mechanic would not want to touch your car, for good reasons.