'98 Boxster 2.5 manual - Differential oil leak

[niba]

I didn't manage to find any threads about this issue. Here's the deal: The other day i noticed a drop of oil under my car. The clutch / RMS was replaced 6 months ago so I hoped it wasn't that. When i got the car up in the air i tracked down the oil leak to be on the right side (passenger side) of the differential where the drive shaft enters. In other words : My Boxster is leaking gear oil from the transmission. I also noticed a vibration in the car when pulling from low rpms in 4th and 5th gear at certain speeds. This was not an issue before i noticed this oil leak.

Has anyone experienced this ? I suspect the drive shaft seal and the drive shaft itself is worn (hence the vibration) ?