She's ok with you getting a Porsche. <-- that is significant.
She doesn't like speed yellow. <-- that is insignificant.
Pick your battles. If you press the issue, an insignificant issue can turn into a big issue. Look at it as a compromise -- your wife already agreed to get a Porsche - so if she doesn't like Speed Yellow, get another color.
You really don't see much of the color of the car from the driver's seat anyway...
-Z
PS: Unless, of course, you find a smokin' deal on a Speed Yellow Porsche!
