Experienced drivers - such as Formula 1 championship leader Nico Rosberg and Jenson Button - have no idea what to expect at the Malaysian Grand Prix as the Sepang circuit has been overhauled for this weekend's race. The 5.5km track on the outskirts of Kuala Lumpur has been resurfaced and the gradients of some its 15 corners has been changed. The tweaks have been carried out to make the track surface smoother, improve drainage and make the corners flow better.Although the overall layout remains the same, the changes to the track could dramatically alter the grip it offers, the lines drivers take into corners and tyre degradation, which is always an issue in a race usually run in sweltering heat."It might be a completely different circuit," said Button, who is making his 300th Grand Prix start at the weekend."We won't know until tomorrow. It's very smooth from what I see," said the McLaren driver, who scored his first podium in Malaysia.The Malaysian race, with its notoriously fickle weather, often throws up an upset and the changes to the circuit could create more drama."It will be very different," said the Mercedes driver Rosberg, who leads teammate Lewis Hamilton by eight points in the overall standings and will be gunning for his fourth straight win."We all need to adapt to the new asphalt; we don't know how it's going to handle here."But for a rookie like Manor's Esteban Ocon, the alterations level the playing field a bit."I have been around on a track walk but it will be my first time on this track," said the Frenchman. ..