I replaced the left front trim on my R53. The piece that is on the hood. It was like $18 + shipping from classic if memory serves. The rear is larger so possibly more but can't be too much more. Classics NAM discount is significant.

 

The front wheel arch trim for the R56 is different and attaches directly to the fender. It lists for $30 and includes the cavity for the orange side marker light. In the R53 the side marker light and fender arch sections are separate.