Specialized Rockhopper: Comp or Expert?

Buying the components to upgrade will end up costing 2-3 times the price difference. Why? When you buy the bike, the cost of the components you buy are included in the price of the bike. If you buy the better bike, you pay the difference in price of the better parts at the price the manufacturer pays, which is less than wholesale prices stores pay. When you upgrade, you pay retail, even if you find discounts you pay more than the manufacturer paid for the same parts, and don't forget you already paid for that part you are taking off, which you might be able to re sell, but at a much lower price. If you are good at working on your bike, you can upgrade yourself, but if you aren't, you have to pay someone to do the work. If you do the upgrade yourself and something fails, you might have voided your warranty since you will have modified your bike. Just keep all these considerations in mind when you decide which bike to buy.