Now the weather is getting colder I?m looking for the best undersuit :-)

I dive in a CNX2-Ri drysuit and I have planned to dive the whole winter in
water temperatures around 0-3 celcius, both ice-dives and perhaps some deep
wreck dives.

I have been looking for these new Flectalon suits from Northern Diver, they
should be very warm, but my problem is, should I choose 100,200 or 300 in
thickness ?? and anyone know where I could get one at a good(cheap) price?

Michael