I use the Bilt Hamber Dynax range. They do a clear and a black spray (Dynal UB & UC) for wheel arches and floorpans and Dynax S50 for cavitys. Nothing else comes close and I certainly wouldn't use waxoil.

I waxoiled my Missus KA, 3 years later it has started to lift in places and water and dirt got underneath it accelerating the rust. Ended up scrapping the car because of it.

Going to get some protection on my 6 month old Focus before winter comes. Might as well start early!