The Mavic is actually somewhat problematic, as it required the shell to be chamfered with a special (expensive, long out of production) tool. Before you buy the Mavic unit, make sure you have access to that tool. But all is not lost, as there are several other threadless options possible, the easiest probably being the Velo-Orange cartridge:



Grand Cru Threadless Bottom Bracket - Bottom Brackets - Components

Be aware that if yours is one of the untapered spindles, it will only work with the Viscount crank, and the Viscount crank will not work with a standard, tapered spindle like the Velo-Orange above. If you have any intention of replacing the crank, you'll need to replace the Viscount spindle as well.