I would advocate the fitting of a better quality bottom bracket and chain set.
If the bike will allow, ask your local bike shop for their recommendations on a for a BB that would be at home on a jump bike. The thicker axle and sturdier bearings will be more than capable of normal riding.
My bike is fitted with an XTR chainset and it's had some real hammer and it's not complaining yet, but then at 84Kgs i'm a little lighter. BUT the XTR stuff is expensive
