Sorry if it's Been discussed loads but I'm new, I've seen the odd comment insisting on super unleaded but I'm worried as on my last car (merc) I had issues twice with crap fuel ( reputable garage with a large supermarket errr attached JS,,) and water in plugs etc, I think the problem is not enough peps use it .. So I'm happy to do so and pay the extra but how on earth do I know it won't cause more problems?..