Seems to be some confusion about RTS vs RST. RTS (Request To Send) is an output of the CP2102 like DTR. RST is the reset pin of the Arduino's processor. I would guess that the Arduino software only uses the DTR line to reset the processor. If that is true, then connecting RTS to RST would have no effect. Your scope, or even an LED rig, would tell you which output the software toggles to reset the Arduino. But my guess is it's DTR, not RTS, that you should connect to RST, as you have already done.
Also, I believe the CP2102 outputs, including TXD, DTR and RTS, are all 3.3V. But you say it works, so your Arduino is probably also 3.3V, although that might be high enough to work with a 5V Arduino, even if it isn't a perfect match.