I am new to biking and just bought a 2006 GT Avalanche 3.0 Disc in the XS size a few weeks ago. I have been reading this forum ever since I got the bike and purchased a Garmin Edge 305 (with HR & CAD) based upon the suggestions on this forum. I would like some disc brake upgrade suggestions. I would like to switch out the Tektro disc breaks and get hydraulic ones. I was thinking of getting the Shimano Deore M535 brakes. I will also need to change the shifters, since my bike has the shifters and brake levers integrated into one piece. Since I need to change the shifters, I was also thinking of changing the back cassette to 9speed. Do I have to change the brake rotors? Are there any other things I need to change in order to put in new breaks and shifters? Should I just get 8speed shifters, or are the 9speed ones much better? Thanks for any help.