I run a 14T sprocket... But we don't cruse over 100kph "60mph" on the road..
most of my rideing is hills / tight tracks & river crossings..
The 14 also makes it easyer to rear wheel steer on gravel..
find the XTR bit of a reluckent turner on tight corners ?
I think is more the stock surspention than the frame...
USD forks & a Ohlins shock are in the pipe line..
So I quess 14T or 15T really comes down to where/how you ride....."horses for courses"