I've been working w/the stock cayman struts for the last 3 years now (boxster spyder/cayman R springs for 2 years). I'm considering the possibility of setting aside some cash for an upgrade. What products should I be considering? And what kind of tangible performance benefit should I expect w/this upgrade (~lap time improvement if possible).

 

There are several advantages to adjustable coil overs for track use including adjustable ride height, adjustable damping, ability to corner balance and ease of changing out different spring rates. I wouldn't just do a shock change. The Bilstein PSS9 or today's equivalent is entry level. It is single adjustable, changing compression and rebound together. Other choices are KW and JRZ. I started with the Bilsteins but eventually went with MCS 2-Way adjustable and found the ability to separately change compression and rebound useful. Because of the high heat in the rear of the Cayman caused by the exhaust pipes running next to the strut, remote canisters are recommended. JRZ are also popular. My MCS setup had remote canisters front and rear and allowed all adjustments to be done from either the hatch or under the front hood. Here's some pics.

 

As mentioned, the pss9/pss10 is the next step up as an entry level single adjustable coilover But there are definitely better options out there for a little more $.

Another step above that would be the single adjustable JRZ RS1 package that we use for Spec Cayman. This package comes ready to bolt in with springs (700f 800r) at around $4k.
Tarett has a nice breakdown of all the other suspension bits allowed in SPC which is good for you to use as a reference as you seek more performance out of your car(sway bars, drop links, control arms, etc.) here is the link. http://www.tarett.com/items/un-assig...y-1-detail.htm

Above that comes the more expensive double adjustable such as the MCS setup mentioned above and the 2-way JRZ RS-pro's. These are another step up in cost and performance

 

Thank you for the suggestions! I apologize it has taken a while to reply. I rarely sign on the computer and the mobile app makes it impossible to even reply anymore.

For the SPC guys...how does the JRZ RS1 setup compare to OEM? It seems quite expensive for a twin-tube damper...