I wouldn't part the car personally. Just because it isn't an original car does not mean that it lacks value as a whole, it's just that the value is decreased to most buyers. Personally, except for the vent louvers and wing, I like the car as it is. But I am far, far, far from being a purist. Even though the wheels are a bit dated, I like the look. Besides, in the Japanese tuner scene vintage wheels are making a come back. Maybe someday the 80's 911 look will come back too.
For now, if you want to sell it you just need to find the right buyer who will appreciate it for what it is. I bought an '86 Carrera myself, not unlike this one, in 2011. It was a slant nose wide body. I've made the best of it by ditching the wing and removing the louvers on the rear intake vents. I don't think it looks so bad now, but it's still a work in progress...
Kirk