My understanding is that all 3 door SVT catbakcs will work with the 5 door as they have the same body structure, just the additional two doors in the place of solid sheet metal.
If you check sites like MBRP's, you will find that they don't make a distinction between 3 door and 5 door SVT. BTW, I love the MBRP on my ZX5 (non-SVT). I think it would sound real nice on the SVT as well.
... still plays with cars ...