No, I have not noticed any spotting in the two years that I've owned the car, wonder if the spotting is due to their choice of Leather conditioner/cleaner. The system works even when the AC is not on auto. In the summer, I have the top down in 95 degree heat with the AC running on manual (floor and vent option selected) and the seats on. I actually went home for lunch today and tried the ventilated seats, with the heat on and top up (a few flurries here in DC). On high, the fan was noticable at city speeds, even while driving, but nowhere near as loud as the climate system when that fan is on 3/4 to full speed. I don't think you'll need it on high in a coupe (unless at a DE event and you need the windows down). On medium and low, I only noticed the fan sound when stopped at a light, not while driving. Now, that being said, my wife would tell you that I've reached the point where I have selective hearing. I remember when I picked up the car, the sales guy said some people even use the ventilation system for the seats even with the seat warmers on. The seat warmers (only two heat options) can get warm, even when on the lowest setting. So, this must be to provide some heat to your back for long-distance driving in the summer, as even on the low setting, the heated seats are pretty darn toasty when wearing a thin shirt.
The heating steering wheel is great option too, especially on a Cab. But, even with the top up on cool days that I wouldn't normally have gloves on me, I put it on instead of lugging around gloves. Even in the winter, I'll want to take my gloves off on long drives and the wheel warmer is a nice touch.