[NZ_M3]

The slurr is basically a hesitation either on an upshift or downshift (usually downshift) ... where the rev stays up momentarily before dropping.
It can also happen when you first step on the accelerator from a stand still, and the clutch don't engage straight away (like mine was ... it'd hesitate, rev up .. then engage - basically not a smooth engagement)

As if one's held onto the clutch without releasing for a tad too long (or riding the clutch).

The reset Mark mentions works most of the time (provided that you give it some beans afterwards and don't settle back on lifting off the throttle on down or upshifts). The key is to keep your foot planted when you shift gears.

Occassionally the slurring can also be resolved by the dealership by reinitialising the clutch take up point in the SMG (which is usually the cause - due to the self adjusting pressure plate that these cars carry - they suck period).

Or if you are like me ... it could also be caused by a faulty release bearing - mine was and on occasions the release bearing would stick and cause the clutch to slurr - it is apparent when you drop the gearbox and look at the release bearing - it'll be unevenly worn causing it to stick on the shaft and release fork. Lucky for me I caught it early and had the dealer drop the box ... it cause zero wear to my clutch or pressure plate - but if you leave it long enough it'll chew up your clutch plate for sure.