new here, wondering about the ae86

[Red]

Wolf-
The SR-5 was mainly an appearance package, a stock Corolla with a little firmer suspension and some nice two-tone paint options and different bumpers, with 13" wheels with steel but not alloy wheels available.
The GT-S had the more powerful EFI engine but was offered (at least in 85) in way fewer colors. The front seats have integrated head rests, high style seats that are copies of Recaros. The VIN code will be AE88 and you need to check the dash plate, the body plate, and the engine to make sure you are getting a real AE88 not a Frankencar.
The GT-S also had the radical standard four wheel disc brakes instead of the standard disc/drum split. The LSD rear end was an OPTION, never stock, and if it was originally in the car it is shown on the firewall plate. Sometimes there is a sticker, etc. on the rear end itself, sometimes not. Sometimes they've been replaced, so you need to confirm it if a working LSD by lifting the rear and turning one wheel, then seeing if the other turns with it or not. The GTS came stock with four alloy wheels, and if it shipped with the LSD rear end the spare tire as also always full size--but on a plain stamped steel wheel.
Power windows and door locks were not available in '85, they were rare in later years. Power mirrors were common, and a sunroof (metal) was common but moonroof (glass) never available. Power steering and power brakes were in most of them.

By now...like Peter said, a lot depends on how it has been owned and maintained. If you buy one, get the factory manual (in print again) and start with a major tuneup and flush of all fluids.

[NZ Trueno]

When buying take a long time searching for rust.

Take a torch with you to check all around the engine bay and behind the bumpers. Especially the rear bumper, its a hard place to check but probably 90% of standard hachis i have seen in person are rusted there.