Adjustable rear struts for 986 while on the car (not coilovers)....

[jakeru]

Truechoice or Proparts (authorized Koni rebuilders & modifiers) might be able to convert the off-the shelf Boxster Konis to externally (knob) adjustable. In fact, they can revalve and may even be able to "soup up" to double adjustable, if desired!

Might give one of them a call and have a conversation. I would check it out, if I were serious into autocross...

If you're looking to get more exotic, there will certainly be additional opti0ns out there. They will be generally not off-the-shelf, but more custom, and cost probably a lot more. JRZ is one such option. Penskes. You could take a coilover type body and weld on stock spring perches to convert a coilover type shock to use a stock type spring and stock type spring perches, maybe even.

Off-the-shelf Koni sports are a very good value basis for a customizable shock for racing purpose like autocross, though. Hope these ideas help... best of luck!