The roof on my aero was tight to start with but with use it has eased considerably. With reference to the roof leaking I cant say I've encountered to many problems, you do get some water ingress around the top of the window but this is fairly minor. But then mine gets driven with the roof down most of the time.
I'd agree with John, the roof on the later Aero 8s is generally very good. Any ingress tends to be due to poor alignment of the frame or damage to the seals. A Morgan dealer (I know they are rare in the USA) should have the experience and knowledge to sort both; however, an intelligent mechanic should be able to sort it (even if it means a call to the factory in England to discuss best course of action).
The stereo can be improved by replacing the speakers with better quality items (same size), the addition of a small amp and replacing the slots that hold the clock and tyre pressure monitor with good quality tweeters. The sound quality will be improved but the nature of the car means it will only ever be average rather than stunning.
