i have a 1987 mazda rx 7 and i need some tail lights. i really dont want to buy the stock lights for it. some one told me that the 89-91 round tail lights would fit but i wasnt sure so im asking you guys because you seem to have all the answers to my other questions so if you could help me out i would appreciate it.

I'm about 90% sure they fit
I believe they are the same size, they should just be one is circle and one isn't, but the whole peice should be the same

The S5 taillights fit on an S4 but i would sugest you do a little more research on the topic.