Didn't get mine through Porsche. Got it when I got my spin-on oil filter adapter from LN Engineering. See...
http://986forum.com/forums/boxster-parts-sale-wanted/59998-ln-spin-oil-filter-adapter.html
...to see what they look like. They're pretty handy--have never regretted getting mine (the adapter, as well as the magnetic plug). You should be able to just Google LN Engineering. They've got pretty nice stuff for the Box. I also use (and recommend) the NAPA Gold 1042 Filters.
Correction: The NAPA may be fine, but what I actually use (and meant to say) was I use and recommend the Wix 51042 filter along with the spin on adapter.