Same problem on the standard YRV as the Turbo. The disc cunningly looks ok on the outside face but rusts on the inside face. Your car will fail the MoT on this. No problem though as new discs are cheap and simple to replace...if you use perfectly good pattern parts and not Daihatsu. Look on eBay. Unless there is something seriously amiss the inner and outer pads should use the same disc surface area.
The bumper protectors look quite good but don't actually protect the bumpers much. If for instance you kiss a wall with the front bumper as you swing the car round the bit that hits the wall is the extreme front lower corner of the wheelarch!
Driving pattern obviously has a bearing on brake disc condition.
My driving style is brisk, anticipatory and economical (mostly 47+ mpg). I don't need to use the brakes much and so the pads don't wear much. However I only use the car a couple of times a week, so if the brakes are cold and wet when I park up, they have plenty of time to rust.
