[thstone]

I am in the process of doing the same, here is what I've learned...

The BK roll bar extension is pretty standard for the Boxster for our needs.

The shoulder straps of the harness simply wrap around the existing Boxster roll bar (the horizontal piece under the hoop).

You'll need a performance or racing seat with harness holes in the seatback to install a 5/6 point harness and a hole for the submarine strap between your legs.

I'm looking at a Sparco EVO2 Plus/EVO3 or similar seat to start and then go from there. My car is also my DD so I need to keep the mods reasonable.

Let me know what you're thinking...