I used a franchised business called
Fibernew to do some serious repairs on my 300X to both leather and vinyl. While product is important, quality of repairs is mostly dependent on the patience and skills of the guy doing it, especially when it comes to color matching. The guy in DFW area was really good and I was very satisfied with his work. Here's link to what my previously twinturbo.net
post; but apologize for the broken photo links.
Here are links to before and after pictures for the leather and vinyl repairs he did. As I mentioned in previous post, ignore the overall color shift due to using different cameras for before and after.
Seat leather repair
Vinyl repairs