I made the decision last year to fit some shiny new alloy wheels. We were driving over the Spanish Pyrenees and would be coming down the French Pyrenees, which involved going down some extremely steep hills and although I was using my engine for braking we still ended up pulling over with excessive brake heating, smoke pouring from the wheels and the potential to get brake fade.
So I thought fitting alloys will give more air flow to the disc brakes when descending these mountain hills. I also get the bonus of getting rid of the horrible rusty old steels for the shiny new alloys.
I have a Boxer Peugeot motorhome and to get alloys you need to know what type of wheels you need. The web link below is full of great information for anyone looking at buying some alloys. I found out my van is a Standard van and would require PCD of 5x118. This site does sell the wheel but i ended up going to this site for the wheel types I wanted.
Now all fitted and I think they look great and make the van look a lot more smarter.