Potential Owner, a few questions

I drive a 96 Cobra. Since I got the car a month ago, my GF has fell in love with Mustangs. She is looking at a 2000 v6 Convertible with the 4 speed auto and 90,000 miles on the clock. It is in great shape, loaded, all factory, guy is asking $8000. Good deal? How do these cars hold up to 150k+miles? How are the convertibles (I always have thought that they leaked, but nothing to base that on)? She isn't interested at all in racing, so much that she gets aggravated when I talk about running mine, therefore speed isn't an issue. Main concern is reliability, it will be a daily driver. Also, what MPG are you guys getting? Thanks for any input.

She really likes the car, but I was really hoping gas mileage would be better. I have $7000 invested in my 96 Mystic Cobra with 120k miles and a decent list of mods. With it I get around 20 mpg city (worst I have ever gotten is 18) and 26 highway. We may wait for a deal on a GT to come around if mileage is gonna be the same. Any other opinions? Thanks.

I am hopefully going to look at it this weekend. Any idea if the wheels off my 96 cobra will bolt up to the 00 v6? I may do some swapping, I am wanting some fr500's or saleens.