[DonC]

Going on my 7th season with the soft top and side curtains. I've driven with it on in heavy enough rain that all I could see of other cars was a ball of spray. Couldn't even see the other car until I was next to it.
Only very minor leaks inside but, being as it's a replica of a British sports car, by law it has to leak some. Nothing a hand towel couldn't handle.
Have had the car up to 90 in a short spurt with no ill effects with the side curtains installed. Wouldn't recommend running over 50 without the side curtains installed.
I have a heater and have driven the car in temps down to 35 with the top and side curtains and been more than comfortable. Once the engine is good and warm only run the heater blower for short periods because is can get too warm if it's on constantly.
Also have heated seats and they make for a comfortable ride down to about 50 degrees but you'll need something for your ears at that temp due to wind chill. Never have needed them with the top on.
Being from the northwest we get our share of wet weather in the winter and the top and side curtains have extended my driving season by at least a month. Since our normal driving season is a little over 3 months that's a noticeable improvement.
Now if I could just figure out how to keep road splash from cooking on the side pipes I'd really be in high cotton.
DonC