I've seen some higher K leather splats on cars in the USA. They looked really good, you had to look closely to tell their age.
It's certainly easier to get new splats made after a few years, then repainting.
Actually with the km's Wazza does, wear and tear is a real issue.
I think if you are careful you can really minimise any marks to the paint underneath. Make sure the paint surface is clean and dust free before applying. And make sure you remove them when you wash the car. Also before re-fitting wipe the backside of the splat to minimise grit getting between it and the paint. But you do need a splat that is well fitting, with a soft foam backing that stops any contact with leather to paint...especially stitching.
Trularin, I just used velcro on the edge of the splat where it folds under the fender. I did use contact adhesive to stick the velcro to the inside of the fender to ensure a strong bond. Worked really well. The splat just had a strap at the bottom at reached under to a press stud on the chassis.
Here is what my splats looked like on my old Cobra.
