IMO you can't beat building a kit, you get the satisfaction of working on it and you will know every part on it and how it works....you won't need anyone to answer questions about how to do repairs.
I ran a 35t in mine for along time but now I'm running a taller gear and 17x1 motor and the fun factor has gone way up, still trails good but now I get nice rooster tail and donuts. As soon as the money is available I plan on putting a novak brushless system in it!