Need some opinions on price

Sorry about the length, I hope this helps

To be honest I wouldn't even buy the car. It doesn't have to original motor in it, which is the heart of the car, and if it has a bunch of other mods, you know it has been beat. Does the guy know the mileage on the car (excluding what the new motor has on it?). Anyways I have bought and sold 9 Mustangs in the past 4 years. 7 of the 9 were bone stock cars, that were in great shape inside and outside. I was able to sell every one of those cars to the first person that looked at them, and I sold them for just under blue book..(within 1,000 dollars). The other 2 were heavily modified...and I had a hard time selling them..people didn't like all that stuff, they were scared they'd been beat of course, and they didn't like the fact it had all the mods...even though the motors were original with stock internals. Anyways man, if thats what you want, I wouldn't pay more than 8,500 for it. I have a 97 Cobra in great condition with minimal modifications, that has 63K on the clock and I am asking 12,500 or best offer...I just can't find anybody with any money..nobody has even called me on it, and the car is in the Auto Trader for less that all of them. I would shop around if I were you.