The two major things to look for are the engine block and auto trans fluid.
The original engines were built with Nikasil. They had problems with rough idle because the sulfur in the U.S. gas was etching the cyliinder walls. A leak down test will show this problem. The engines that had this problem were replaced with Alusil blocks. You can check for which block you have by getting the block casting number off the engine. Go tp
www.Koalasport.com, they have a very complete writeup on this problem.
The automatic transmission does not have a fill pipe or dipstick. It was supposed to be a "lifetime" transmission. The "lifetime" is up if you have over 80K on it.
I replaced the filter and refilled with Redline D4 trans fluid.
I was having "Trans Program" problems before I did this and this fixed the problem.
You will need to replace the fluid a couple of times unless you flush the trans. I did a second replacement after 3Kmiles to get the concentration of the D4 up.