From a non-S2k owner...
All for stone chip/decent undersealing arches etc but without those rubber trims, bear in mind there's no actual seal along the seam between the inner and outer arch panels.
That seam is just spot welded along (again assuming it's the same as ludes) so water gets drawn in between the spot welds (surface tension will draw it in,not let it run out).
The rubber trim (assuming it's the same as ludes) isn't just rubber, it has a bead of wet seam sealer pre-injected along the bottom of it, so that seals along the panel seam when you fit them. For that reason though, you shouldn't re-use them if you do remove - refit new.