mlh122

I'd say on a 4900 disc, the only things I'd look at are the saddle and brakes.

stock saddles usually suck pretty bad. i'd ride a little to see if it's comfortable to you, if not, ride a little more and make sure you don't just need to get used to it, if still uncomfortable, get a new saddle.

i couldn't find a 4900 disc on trek's site, but stock disc brakes sometimes aren't that great and sometimes are pretty good. if you got Tektro's, you might want to upgrade soon. If you got BB7's, you might not ever want to upgrade except to Hydro's.