Forget about the Saleen tonneau! Get the 2 pcs tonneau from Cervinis, that one is also very high quality and will fit in the trunk. That's the next item on my buying list...
I have the 2 piece Kar Kraft cover. Yes it squeeks, no it doesn't fit in the trunk. If you turn the 2 pieces sideways, one fits across the top of the back seat, the other goes almost vertical behind the front seats. You can put the top up and fit 2 people in the car.
I've been told there is a certain speed at which rain no longer becomes a problem and simply goes over th top of the car. Saleen Mike has explored this issue, maybe he will chime in?