Your hesitations are the same ones I have. Exhaust looks stock...but you never know what is or isn't replaced. Look at the heatshield over the turbo...see if its been cut or removed...if so, it was more than likely at Stage 2 or more. Never know if it had engine management. There are no pictures at all of the engine so we can't deduce anything from that.
Have a reputable mechanic check it out and even have compression and leakdowns tests done...this will show you how good the cylinders and block look. If the dealer is a good no-bull**** dealer, they will have no problem letting you do this.
But there's no harm in checking it out. What's the worst thing that happens? You walk away without a car that could give you a ton of problems.
Be patient and wait for EXACTLY what you are looking for. Don't settle just because you let the excitement get to you. Goodluck