From funcarsonline:
Pretty easy installation. I have mine just to the left of the mirror using the supplied suction cups. Power cord: from where you want to hang the V-1, push the power cord behind the windshield molding with a plastic putty knife. Once you get to the dash, its easy to run the cord across the underside of the dash using existing wires and accessories to hide the cord. Gently pull off the small LH side leather panel and the carpeted panel on the console. Also remove the batwing panel on the front. You can then remove the CD holder and storage tray by pulling them gently toward you. In the console you will find either a green and black or green and brown wire. That is a "switched" wire. Tap into that wire using the V-1 supplied clamp. It is difficult to find a suitable ground but there is a console mounting screw that attaches to metal on the LH side of the console. I used that screw for the ground. Once you get it hooked up, turn on the ignition. Hopefully, you'll hear the V-1 power up. If it works, replace all panels and trays and you're done. Took me less than 30 min.
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http://www.geocities.com/porschecarrera996/v1Install_files/v3_document.htm
http://www.industryfigure.com/berkeley/Porsche/Accessories/valentine.htm
http://www.986faq.com/7-0/v1.asp

Mobile Scanner & Detector Laws:
http://www.afn.org/~afn09444/scanlaws/