yes, there are differences, and they're not interchangeable.CDR Stang said:Are there any electrical differences between the 99-00 and the 01-04 speedo gauge clusters? Or anything that would make a difference between the two years? Would it be as easy as getting a 150/8k overlay and having the car's computer recalibrated? As far as driving 150+, been there, done that. I'm mearly looking for another cool mod to do during the winter. I seem to pick the projects that few or none have done before. I like it that way.