Most likely for the airbags (suspension). If a pump wasn't installed then that's a valve to charge an on-board air reservoir. That way he can quickly bring the car up to a non-citation issuable height if a LEO sees him. [Mary Beth Buchanan SUCKS BTW]
I could be wrong but I believe that is a hydraulic cylinder with a bronze bushing (CCE Hydraulics: CCE Cylinders) I read in another article about that car indicating Tommy originally had Hydro's (The world adores matt hayward Tommy Chong’s pimped Prius) installed but had them taken off because he didn't like the stiff ride. He probably should have just had some accumulators (http://www.streetsource.com/uploads/Ownerprofiles/IGotIssues/372009121516PM49931.jpg,black rubber parts connected to the pumps) installed and that bad boy would have just floated along like a Caddy. Sometimes I miss having adjustable suspension and the big wheels etc etc, yet as I get older I realize saving the cash for my daughters college years at Notre Dame is probably the smart decision.
Nope that's just what it looks like "sitting down". When you jump in you hit the switch raise the car up the your preferred ride height and off you go.
I am glad you all like what we did to the Prius. If you have any questions please let me know. Thanks, Evan Hippy Motors
Yeah, I have a question: Would Tommy like any visitors from back home? I'm hoping to drive down this summer.