I think the new XTR brakes are strong enough for Downhill usage. There are however two types of XTR brakes: - M985 for Cross Country Usage. You can recognise these on the slim design of brake lever (no tool less reach adjust and no free stroke adjust. - M988 these are the brake that I have on my bike which have the Servo Wave function (125% more brake power than previous XTR brakes M975) and also Tool less reach adjust and Free stroke adjust. If you combain the M988 brakes that I have together with Ice-Tech disc and brake pads you will have no fading issues anymore and also brake pad wear out will be much less. I hope this helps you in choosing the right brakes. I have tested these XTR brakes on a 4.5km descend with 160mm front disc and 160mm rear disc and I had ZERO problems! Quite remarkable if you consider that my body weight is 103kg. Brakes are aggressive and because of the 1 finger brake lever very easy to handle!