Rear brakes are over rated 
on RGS's basically...
No I do find that Brembo carbon ceramic's ( the blue ones ) seem to work the best on them also you need to make sure that both angles at the brake pedal and the pivot are as close to parallel with each other as possible and not going to far over center.. as you can loose some mechanical advantage... also I do find that changing out the original old brake hose for a braided one kind of helps a tad also the angles on the linkages tend to help. But basically rear brakes on most RGS's and the Corsa for that matter are not much better than useless... bit like having an ashtray on a motor bike... ( actually a Harley rider told me the other day that they now come with them now so I need to change my saying ) but the US Executive has an awesome rear brake..
on RGS's basically...No I do find that Brembo carbon ceramic's ( the blue ones ) seem to work the best on them also you need to make sure that both angles at the brake pedal and the pivot are as close to parallel with each other as possible and not going to far over center.. as you can loose some mechanical advantage... also I do find that changing out the original old brake hose for a braided one kind of helps a tad also the angles on the linkages tend to help. But basically rear brakes on most RGS's and the Corsa for that matter are not much better than useless... bit like having an ashtray on a motor bike... ( actually a Harley rider told me the other day that they now come with them now so I need to change my saying ) but the US Executive has an awesome rear brake..