DON'T remove your full fenders. Road salt is your bike's worst enemy, and a seatpost fender will not keep it off your bike. If you don't have room under your current fenders for a bigger tire, don't sweat it too much--I rode most of last winter on 28mm road tires. The only thing that really stopped me was the ice that regularly form on the Hot Metal Bridge.
I also stick with wax lubes for my drivetrain. Yeah, they wear off much faster, but they also don't pick up as much gunk when you're riding.