There are members of YD (JohnG,LawrenceD etc)who are very very experienced in the realms of cold water...and the problems it brings.Now I appreciate that as far as the UK is concerned the water temps here are considered "cold" year round(by medical definition!).However,I'm using cold here in the descriptive sense.I've dived under ice in the Uk but it does'nt come anywhere near this,or what the aforementioned members will be doing!
Quite regularly we see posts by people asking if their kit,particularly their regs.will suffice for cold water use.Magazine tests are well and good but I have a feeling that many,like me would rather invest cash and trust in something we've seen work personally eg,someone we know has used one.This is the beauty of YD,we have experienced people who are willing to guide us with their experiences,without "sneering".In addition I found this which I think is really interesting.
The first link here(some will have seen it..apologies)covers the dive kit used on this project,the whole site's worth a look as the photos are amazing.The second link is re.the results of reg tests carried out over several years on the project.There's quite a few popular regs.not on here,I don't know the criteria etc.that was for using the regs.tested but it makes interesting reading nonetheless,with some suprising results.
Hope it's of interest,Hobby.
http://scilib.ucsd.edu/sio/nsf/diving/index3.html
http://scilib.ucsd.edu/sio/nsf/diving/robbins.html