I found that 240 speedos already under read on stock tyres anyway so by going even smaller it'll read further out, your engine will be revving higher so you'll use more fuel per mile, less top speed and itll look odd with little tyres on the wheels.
But.....
It'll accelerate quicker and stick like poo to a blanket on A539s which are an epic tyre. If only they made them in bigger sizes
