My 1990 Hobie 18 was dubbed a Hobie 18 Formula... the main difference was the wing design as compared to the magnum wings... the formula wings had a longer top section... about another foot on each end as compared to magnum. The boat also came with some upgraded main and jib blocks and I think black annodized as opposed to silver. Other than that, it was a standard TheMightyHobie18.