This belt tensioner should fit all transverse mounted motors but I am always surprised to find new parts that I forgot about or didn't know about so I recommend measuring your tensioner and making sure everything is the same. 
This should also work for the AE86 although the diameter is slightly smaller so you may need a shorter belt. I haven't tested this but don't see why it wouldn't work. 
If you want to try it and it doesn't work return it for a full refund as long as it isn't scratched or damaged. 
This has a 10mm hole. Some OEM pulleys have a 12mm hole. You can either switch to a 10mm tensioner bolt or drill this to 12mm.