I'm not an expert but I believe the owner is saying he's using ROW "euro" pistons giving the car a higher compression ratio.
I like the look of the car, but with the script and the chin spoiler I think it needs the original Carrera tail to finish off the look.
The car looks great and if it's what you want I would consider looking into it further. Stating no rust ever is fine, but I prefer to see pictures of the underside. before I buy that plane ticket to go look at it
I personally would go for an `80's Carrera not that a CIS car is bad just one less thing to deal with on the motronic cars. The 964 is starting to get too modern for my tastes but it's all about what you want out of the car.