I'm just the opposite of mountainman. I bought a hard top almost 2 years ago and have never taken it off, although at around 50 lbs. it's an easy 5 minute job for 2 people. It's cooler in the summer (I don't like getting baked by the high altitude summer sun where I live), warmer in the winter, I don't feel like I have to put the top up every time I park to go into a store, it's considerably quieter, and it seems to make the car feel more solid (my imagination?). I also think it makes the car look better. I've posted pics of it a few times but I'll post some again.
Hybrid Mode
