[Heiko]

It's not hard to do if you have good mechanical skills and the right tools... but if you dont feel comfortable take it to a local guy you trust or maybe another Boxster owner in your area who's done one before.

To swap out the AOS unit:
-put roof in service position and open engine bay
-remove crossover breather pipe from AOS to intake manifold
-disconnect oil filler pipe and fold rear portion out of way
(do not move or jerk the front piece as you will break the mounting flange on the motor side)
-take a pair of spring clip pliers and undo the vent pipe entering the AOS from the right side of the car
-Now the hard part...
-undo the aluminum cover plate under the tranny (have to loosen the two big aluminum cross braces as well to get the cover off... once this cover is off its easier to gain access to the lower part of the AOS
-Once you have access, undo the two 10mm bolts in the lower portion of the AOS... and then use the spring clip pliers and undo the bottom rubber hose from the AOS
-Now simply remove the AOS via the top
-Replace the new one in reverse order BUT (to save you lots of grief)
-put the spring clamp on the lower rubber hose as far down as you can get it
-then put the new AOS unit in from the top and connect the side pipe... then get back underneath and work the lower spout into that short little rubber hose and make sure the clamp goes back securely.... then replace the two 10mm bolts and reseat the filler hose and breather hose from the AOS to the intake
-Re-assemble the bottom cover on the car and you should be good