I finally figured out why.....
 

I cant park my boxster straight. Wider track in the rear makes the car look crooked in the space when it is really straight. Never had a problem parking my truck, so I started to wonder....

Haha! Glad it's not just me. Been embarrassed many times by my parking job in this car - just back straight into a stall and somehow it's cockeyed. I've learned to not trust my driver's side mirror alone, but sometimes it still happens.
Honestly never really thought about why it happens till you said this.

Ive used the mirrors, the lic plate backup cam and it does not work.

Finally I simply look straight ahead to the lane markings across from my spot and reverse perfectly till I feel the force telling me I have gone back far enough and the car is inharmony with the universe around it.
Perfect every time now.

Look not with your eyes Jedi master, at what you cannot see, but feel you can, when your Boxster is content! :cool: