Looking at a 2001 GT

7K sounds a little high for the mileage(make him an offer), you are paying for the forced induction(which with all the costs associated with it can run several K's), does look clean though especially the seats/interior for the mileage. I would look for the the usual things; signs of abuse/wear and tear(you know, weird noises and actions etc). I also climb under with a small powerful flashlight and inspect everything for wear. cracks, rust etc. These can go 200K but it is not unusual for the upper end to need refreshing ie chains, tensioner. guides, and maybe valve seals. A lot will depend on what you are able to fix yourself.
I recently picked up my '02GT with 83k and absolutely gorgeous shape for $5340.00 after looking for many months, of course no supercharger for that price.

These engines (w/o any abuse, of course) can run 300K+ miles w/o any major repairs. Maybe a timing chain tensioner and guides if the oil was neglected.

I paid $4500 for my 2K convertible a year ago, with new tires and wheels...interior was rougher than the one you've pictured and stock motor. If not addressed in the vehicle build up, you might plan for struts/shocks and rear upper/lower control arms as an opening argument for ownership...assuming engine and drivetrain are strong. The GTs are fun cars and mine has proven super reliable after hammering out a couple of things the PO was ignoring or couldn't afford to fix. Enjoy.