245WHP is completely reasonable.... If your motor has been built with a solid 8k plus(motor itself). So BS is my first statement. Why? Because you just squeezed out approximately 60-80whp with intake header and full exhaust with a tune(Literally impossible).
Now to be on the nice side your buddy or whoever is selling the car could be making 245HP(Crank).

If the car(body) is in great shape than a solid price for it 4k max... Shitty body with shitty paint and dents more than a model...your looking at 2k at best.

Remeber just because you have a 2k motor(excluding tranny) is a 1k shell does not equal 3k in value..

It all depends on how well the car itself runs, quality parts, motor&body itself, etc.