Ah the age old "rust" issues T4's are usually good on that front and i am sure no way compare to comparible makes, however do sucome to it to some degree, the wheelarches being one place unfortunately that every vehicle will at some point rust from due mostly to stone chips that are not repaired quickly enough...

Ok so to a cure overarches are available from both Vansport and Jk unfortunately not in a range of colours though Vansport do silver/chrome ones which i had on "White Noise" and which look good on a white van and in my poinion are the best and Jk's oe black abs plastic "Gti" look-a-like ones which are ovberpriced in my view anyway thats about it on the choice front i am afraid [below u can see a image of White Noise with its arches on]like em or loath them that's your choices

Failing that it will be a paintwork specailist i'm afraid being your only recourse fortunately your van will be L902 VW Common white which should be easy to blend into the surrounding paintwork which will make it a bit cheaper....