I have been thinking of fitting one.
I want to be able to drive the car for some distance, which IMO means music for added comfort
(especially if you have the soft top fitted).
I was thinking about fabricating a centre console. This way I can fit a stereo, have a small storage bin and a shelf or something for sunglasses.
I'm still at the thinking stage at the mo as I need to fit the dash, pedals and pop a seat in there to see just how much room I will have.
Obviously the easiest fit will be on the passenger side. If you fit one with a remote, this shouldn't cause much problem.
As for speakers, I was thinking of a small sub behind the seat, speakers in the door and possibly tweeters on the dash. Nothing too much, but from my experiences of open top cars, above 55mph you need some volume.