Honestly, I wouldn't touch a thing on the bike and just ride it as is. It's a good solid bike. After riding it for a year or two you feel you've out grown it then upgrade the whole bike. It's just not very cost effective to upgrade parts unless something breaks. It's always cheaper in the long run to buy a bike that has all the parts you want on it already. Sure, a wheelset would make a huge difference, but a cheap light wheelset is about $550 for a Stan's NoTubes wheelset (best bang for buck hands down btw).