I just bought a Korean (that is where I am stationed) spec Giant XTC 2 to replace my 1997 K2 AFC-4 that I still love to this day. The Korean version has much much better components on it than the US. ie XTR front and rear derailer, juicy three brakes, deore crankset, and a fox shock with lockout. But, the wheel hubs are just not up to the task. It has Shimano M475 hubs now and I want to change them out. I was thinking XT or XTR only because my K2 has the older version of these on it now and they are wonderful. Any thoughts? thanks.

Those hubs should be fine for the time being. Use them until they wear out. But if you really want to replace the hubs, just sell the wheelset as new takeoffs and just buy a new wheelset.

You can swap out the hubs but you'd have to factor in the hubs, spokes, and the cost to have them taken apart and rebuilt (unless you can do that yourself). And if you're going to do that, you may as well just buy or build up a wheelset you really want.