DUH? One is a convertible and one is not. (j/k) Spyder is heavier and suspension mods are little different to do. They will generally perform the same but the spyder will be a little slower.
I raced a 95-96 GST coupe yesterday and we were neck and neck until 3rd gear when my stupid Dejon UIP rubber coupling came off. The guy also had more mods than me and I kept up with him. I'm not sure who would win if it was stock vs stock though.