Ive been havin the same problems with my 2.2 3dr SRi. On cold/wet days as soon as I got into the car it would steam up which usually means a water leak. I got so cheesed off with this that I got the hose pipe out and started to drench the car in water in various places. I got to the rear quarter window on the passenger side and saw a small drip of water running down on the inside of the pane. I took out the interior fixings and tested the spot again...bingo I found the leak. Out came the window, cleaned the existing seal and bodywork and put a small bead of black silicone on the existing seal, In went the window.....I thought Id better check the otherside and hey-presto a leak in EXACTLY the same place, so out came that window and did the same. Oh and while I was testing the passenger side I noticed that water was also comming in where the wiring comes from the car bodywork into the the boot lid! So I checked this and found that the rubber gator that covers and seals the wiring didnt seal against the bodywork properly, out came the box of "o" rings and found a couple of them slipped on in the rubber resesses at either end did the job nicely. Left the silicone to cure overnight, this morning it was chuckin it down with rain, checked the seals and windows and hooray no leaks and no steaming up! Job done.
Hope this helps anyone whos willing to try this not so difficult solution.
NOTE: It would be advised removing the interior fixture first so you dont end up with lots of water resting in the interior fixtures like I did!