Old thread!
someone has brought it up so I will add my point
The Roughness Vs Smoothness arguement is almost pointless. All it does it to serve as a distraction away from the important things you should be concentrating on
Smoothness, or roughness are consequences, and NOT causes of going fast. Let me explain.
A common mistake people make is they say to a driver -
"You must driver smoother"
That alone is an empty statement. Rather than sitting, and trying to understand the fundementals of grip, and how to attack a specific corner people get caught up in a certain style, in this case - smoothness. Trying to be 'smooth' may make you faster up and until a point, but it will not take you to that extra level needed to put in proper fast laps.
To go ULTRA fast you have to throw away the concept of being smooth, or rough, and analyse each corner, each car/kart, each race, and each track in it's own right.
90% of the time as a consequence of doing this - analysing each corner/track/race etc... - you will drive in a way that looks smooth. But that is a consequence, and not a cause
The question any driver should ask is
What is the fastest way from point A to point B?
The answer is simple
The fastest way... is .. the fastest way!
A 'world class' driver will be able to draw from experience, feel, and knowledge to be able to extract the maximum from any situation and not be drowned by pre-conceptions of what is either the right way, or the wrong way