so, here's a neat little thing that might make it easier to put a 5-speed in a 6-speed car (or visa versa) the slave cylinder has to be changed but, due to different fittings, requires that all the clutch lines up to the master have to change too:
Porsche 996 New Quick Connect Clutch Line Adaptor Kit | eBay
and here is something which is cool, but dunno if it will fit on a boxster (no idea what our cv boot diameters are ...):
New Aerodynamic CV Boot Fits Porsche 108mm OD CV Joints | eBay