Reddit mentions of Shimano BR-5700 105 Brake Caliper

First off, congrats on the bike! I have the exact same one in Bronze and it's been great to me so far. Honestly, it's a pretty decent bike out of the box. I'd go about changing things as you need (or want) to.

Personally, the only thing I've really upgraded on my bike is the brakes. There's some fast, long hills on my commute, so having the extra stopping power as really helped me feel safer when I'm descending.

Here's what I changed exactly:

• New Shimano 105 brake calipers to replace the stock Promax ones. Night and Day difference in stopping power.
  http://www.amazon.com/Shimano-BR-5700-105-Brake-Caliper/dp/B009VB73CC
  
  
• Tektro RL520 brake levers to replace the stock horizontal brake handles. It feels easier for me to climb when I'm on the hoods vs the drops or top bar, but it's just a personal comfort thing.
  http://www.tektro.com/_english/01_products/01_prodetail.php?pid=10&sortname=Cyclocross&sort=2&fid=3
  
  
• Added a 17t freewheel on the flip side (just in case). I haven't had a need to use it yet though.
  
  Some people recommend changing out the Bottom Bracket, but I haven't had any issues with mine so it's staying :)
  
  Here's a 50+ page thread about the Fuji Classic/Track that you can read up on. I've learned a lot of this:
  http://www.lfgss.com/thread837.html
  
  Now get out and ride!