Indeed, make sure the stem fits the new handlebar (your LBS can measure it for you). I have seriously modified my Trek 7300FX in recent months, recently replacing the stock riser bars with drops though keeping the original stem. BTW, the Trek 7300fx uses Shimano Alivio rapid-fire shifters, which are fine; if you have the dough, however, I'd go with the slightly lighter Deore LX shifters. If your current shifters are attached to the brakes, you may want separate brakes this time around -- something better bikes usually have. I second getting rid of a suspension seat post.

Enjoy the ride.