My friends had Somerford do a reshell for them in 2003, and at the time they fitted front wheelarch liners. Their car still has no rust in that area, 16 years later - and for the first ten years they used the car a lot in all weathers in the West of Scotland. So when I bought a Somerford rebuilt car in 2014, I asked them to fit wheel front arch liners too. My car is a midly tuned 1990 Cooper.
I've had 2 problems because of them, though -
- I found that on a long motorway run in warm weather (IMM 2014!), the standard radiator wasn't coping - i suspected because the wheel arch liner cross in front of it, and must reduce its effectiveness. Slowing down brought the temperature down. I swapped the radiator for a "SUPER 2 CORE" and now it over-cools... IMM2019 will be a test for it though!
- I can't see because its all above the arch liners - but I don't think the dash vent pipes are connected - maybe not even there (You can tell by the wheelarch noise when you open them, and the lack of ram effect). This annoys me, because I know how well these vents can perform from my previous 5 Minis.
But I think its worth the hassle, to avoid the rust.
