I am in the same predicament with the same year Z. I know the Sparco R100 seats fit in a 240z, but I don't know if they would fit with less room in the 280z. I also don't know if I fit the R100's lol. I have the opportunity to pick up a pair of Cobra Daytona seats for cheap. Since DeathByNissan55 and I are in the same boat, does anyone have anymore information on these seats for bigger people in 280z's lol?