If you want sound , buy a Gianelli or Laser , Tecnigas etc. Yasuni R has a more civilized sound wich a prefer cause more noise doesn't give you more speed , but is does make you look like a dork ..
The R responds very well on a stock Aerox , easy in use and good quality! I suggest you also buy a good variator with some rollers and return springs so you can adjust the variator very well.