I've owned one of the first beta 300 rr 2013 and the bike before was an KTM 200 EXC 05
I highly recommended radiator Gaurds, foot peg and maybe a few bling bits.
the only problems I've had is suspension, mainly leaking fork seals and bottoming out the forks, I've been told the newer models have been improved.
to fix it I've gone to a set of racetec spring ( heavier rate ) and heavy duty fork seals, I still occasionally have to clean the seal with the fork doctor tool.
I find that the beta handle excellent out in the bush low or high speed but I would recommend a steering damper if you like the fast rocky tracks.
enjoy the new bike mate