I'm in the market for a new Mountain Bike and I was just wondering what everyone's opinion is on the Trek Fuel 90 or 80. I will most likley be doing a combination of trail riding, uphill/downhill over mountains, and eventually some small drop offs. Do you think this will be a solid bike for this? Also, is it at all possible to upgrade the rear shock at some point to get more travel? or do you think 3 inches of travel rear, and 4 inches front will be sufficient enough to handle downhill trails at a good pace?