Few things to look for.
If there is still the stock plastic under the doors (rocker panels) look for rust as well as around the wheel wells. Look for dented and/or rusted gas tank skid plate, and tank. Look at the frame rails for rust (mine is rusted out at the back where the stock bumper mounted) as well as the windshield frames which are known to rust around wiper arms. Look for rusted out seat mounts especially with soft tops.
Also look for the body mount bushings and leaf spring bushings (my body bushings have slowly disappeared)
If sprung over, look at the perches for twisted perches. Look for binding or excessive play in steering; possible options are OTT steering, Z-Link, drop pitman or stock; look for tears in rag joint.
Look at engine, tranny, and transfer-case mounts.
Stock engines (1.3L) are known to leak out of dizzy mount on back of cam (fairly easy O-ring fix).
1986-88.5 use the same bolt pattern drive-shafts, 88.5-up use a different pattern (need to know if you ever have to replace one). Check all U-joints, including the intermediate drive shaft joints, for wear and play.
The heater core easily gets clogged with sticks, twigs, and leaves (have to remove dash to clean out I recommend putting a piece of household window screen between the top of the heater intake box and where it bolts to the body).
I'm sure there is more but this should help you get started. I have owned my Sami since May of 2000 and have not had all these problems but have heard of them over time. I have not really had much wiring problems either (other than when I changed the rear lights to LED's).
Hope this helps some, if you have any questions just ask.
