Hi, I've got an RT. Here's my 2cents.
Change batter heads, Remo skins are good. I personally got Remo center black dot batters. You might want to change your snare, i didn't like it. If you can't change it atm, use the black rubber padding (shaped like a fan with 3 blades...) and put it on top of the snare drum. Kinda muffles it and removes the awful sound the stock snare gives. Cymbals definitely need changing, the stock crash can be used like a china I suppose, but you definitely need a better hi-hat and ride. Stuff a big pillow into your bass drum, it will sound better. The single pedal given is ok I guess, I didn't have any problems with it.
To me, RT is a good compact kit. The lack of resonance head on toms (i.e. each tom only got the top side, which is the batter. it's open from behind, so reso head missing) makes it kinda wrong sounding. I used some muffling ring on my 10" tom, so it kinda sounds better. Maybe you could try that too.
K that's about all I've done so far. Feel free to shoot more questions.