[The Radium King]

here's a cool idea i read about in another forum (i.e., i haven't done this myself):

get the sport chrono enclosure from a cayman/987 and mount it on your dash (you have to drill a hole, so measure twice ...).

next, apparently these multigauges fit perfectly:

http://www.plxdevices.com/multigauges.html

it just plugs into your obd ii port and reads whatever parameters from your ecu you want, and you can even upload custom gauge faces for it:

http://www.plxdevices.com/customgaugelibrary.html

when done, looks like you would get a totally stock-looking, totally useful little tool.