Trackdays: any bike will do and the stock RC51 is setup pretty good. Plenty of reasonably priced mods will make it handle better but leave the bhp alone. Getting more bhp out of an RC51 is tough - read: $$$.
Racing: Buy the cheapest and easiest to ride bike you can. First season is a learning one.
Really for trackdays esp. only a few trackdays per season use the bike oyu own or have access to. Far cheaper than buying another. Besides expect to get smoked by the guys on the old/slow supersports.
