Disc Brake Upgrade

Sevenfold Posts: 86
edited May 2010 in MTB buying advice
I have a Claude Butler Cape Wrath XC with Crane Creek brakes that I am looking to swap over to hydraulic discs as a first upgrade. The forks are Suntour XCR MG. Can I fit any size disc (160 - 203mm) & what would you recommend? Budget is about £150 my riding is beginner level XC.

Thanks to all posters.