want to buy a SL500 (1989)
 

As a new member I am looking for some advise on buying a japanese sl500; less than 90k km.
Car has a solid technical base, no accidents, no rust.
The vendor could not demonstrate the electrical removal of the hardtop and the proper movement of the softtop due to program error as a result of a low batterie. Can this be a valid explanation?
Also the car had no stereo. Are there known issues with the soundsystem and what type of stereo should there be put in?
During the testdrive hitting 3000 rpm as resonation sound came out of the exhaust, could that be the catalist?
Thanks for any advise.

I don't have a good feeling about that car.