I would like to puchase AE86- help

[RUSTY88]

Hello
I would like to buy Toyota corolla AE86 i choose levin kouki but I have some questions about this car.

1.) I would like to buy car with auto-locking (LSD) differential how I recognize if car have it or no. ( Only some types= which, only some production years which...etc)

2.) Which emission norm AE86 have= registration authorities

3.) Are there any traps or weaknesess which used or badly mainteined AE86 can have...

4.) which version is best ? ( some GT...etc) - only kouki version

Thanks a lot for ansvers- my english isnt very good so some technical term please write simply

THANKS