Can anyone tell me if there are any disadvantages to putting wheel spaces, front and back on a c4s cab, thanks in advance.

 

As long as the sizing-widths are done properly you should not run into any problems. I'd follow the recommended spacers by Porsche USA. My car came with rear spacers due the the upgraded carrera sport wheels and wider track. Hope this helps.

 

How does the spacer improve the car?

 

From a visual perspective; not handling or performance.

 

In the case of having Carrera Sport wheels on a wide body car like the C4S, the spacers are required on the rear wheels to compensate for the wider body (the Carrera Sport wheels have a narrow body offset). If you're considering adding spacers simply to push existing wheels out further, it is usually only for visual effects (many people think the cars look better with the wheels further out). However, these changes do impact the geometry of the car and its handling, especially when changing the offset of the front (steering) wheels. I've heard that front wheels should not be changed more than 7mm, as steering geometry gets changed.