The cyclone S is a good car however there are a few things which are nice to have upgraded. If you are only racing 540/stock though the car should be good enough in kit form once you upgrade the C-Hubs from some weird brittle plastic.
You do have to watch out when upgrading a few parts though. IE if you upgrade to spool or oneway you should upgrade the center pulley system.
If you go to aluminium pivot blocks then you need to buy pivot balls and some 2mm / .75mm shims