These are really two different cars so I think it really comes down to what you need. Do you need four doors or two? Do you want a pretty strong 6 with pretty good gas mileage or a pretty weak 8 with alright gas mileage (thinking that your price range would get you a 94-98 GT)? Honestly the performance of the two is probably a lot closer than what you think. The nice thing about the SVT Contour is you don't see a lot of them (depending where you live) while Mustang's are like belly buttons, everyone has one. If you value space and economy I think that the Contour is your pick.
If it were me I would go with CSVT.
