I would keep it original unless you're doing a full strip. If that's the case, paint it the color you want. Trying to keep up with fads is exhausting and who cares what color the next guy wants. I doubt a change dramatically affects the value of a non-turbo low miles G-body. If it does, the loss in value is less than the cost of the resentment you'll experience for not painting it the color you really want.

 

You may be forgetting this car is an honest-to-goodness M491... Even more rare than a turbo.

 

No I'm not forgetting. While more rare, it is only "more desirable" to some and only Porsche aficionados. Paint is reversible. These cars are meant to be enjoyed and if you don't like the color, repaint it. It's not a Ferrari GTO where the effect on the value may be measured in 7 digits and the paint job would be priced similarly.