Is it possible to switch off the airbag on passenger seat?
 

I'd like to be able to take a drive with my little boy in a Boxster. Can the airbag be switched off? Ever take your kid on a canyon run?

Pelican Technical Article: Porsche Boxster Child Seat Installation - 986 / 987

Airbag Deactivation Bar for Porsche Child Seats:Porsche Parts & Porsche Accessories - Wholesale Porsche Parts & Tequipment - Cayman Panamera Cayenn

Pelican Parts - Product Information: 996-803-083-02-OEM

They usually come up for sale here on these forums for around $100. Keep an eye on the parts for sale section.

Porsche made a setup to disable the passenger's side air bag, which employed and alteration to the seat to mount a child seat and a modification to the DME programing which made it all work. You can find the kits to do this, but the DME programing requires a PST II or PIWIS depending upon the model year.