I searched no real info came up with my query.

I have Nokian NRW(old school WR's) running (36PSI/32PSI) and find them better in dry. Running at this higher pressure do I compromise winter traction?

This is for my 2004 WRX Wagon.

I don't think you give up much in the way of traction, except possibly in very deep snow where the tires aren't actually touching the pavement, but are riding completely in snow. I run my Nokian RSi's at 36 psi all around because I hate how mushy the car handles on dry roads if they're any lower. And I haven't noticed any problems with that. I'm a big fan of running stock-sized WRX tires at much higher than Subaru's recommended pressure, though, because I'm convinced that pressure was just to soften the ride a tiny bit for old ladies with sensitive butts. :) The car handles so much better with 36-38 psi all around than at 32/29 like SOA recommends that it might as well be a different car.

its six of one, halfdozen of the other.

1) On soft snow thats not too deep you might run a higher pressure to narrow up the tire a bit to cut down to pavement/dirt easier.

2) on glare ice you wnat as much tire in contact as possible, and you wnat the chge in the slip angle to occur at a slow rate. (less air)

3) on hardpank with some dirt mixed in (like in da UP) you want to run inbetween the above two pressures. This give some stiffness to allow the blocks to bite a bit. While slowing the rate of change of the slip angle to prevent full slip, wich just makes ice.