Is there are a certain class you are looking into or just wanna know what kind of seats real drivers use? Just wondering because autocross class rules applies to seats too and since most MR2s are in stock classes, people have to use unmodified stock seats. I believe you can run aftermarket reclinables in Street Touring and then competition buckets in Street Prepared and above. But yeah, seats are a personal thing because people come in different shape and sizes. I'm forced to use stock seats, but it would be nice if I could use a set of Sparco or Recaro racing shells. Kirkey seats seems to be popular with on the budget road racers. And most importantly for competitive driving, seats should also have some kind of appoval rating such as SFI or FIA.
Not to burst anyone's bubble, but the Sparco Speeds aren't FIA approved, but the Sprints are (they look almost identical to the average person). Only matters if you plan on competing in road races though.