Peter, I'd be interested to know why you're asking? I did not have them on my 07 reg +4 and it was not a problem. But on my 18 reg +4 the brakes are just awful in heavy rain. Something I've got to fix this winter. I might just drill the discs as this has worked on other cars but I also need to contact some of the suppliers to see what they have on offer.
Cheers
John
