this is not mine, found it on CL. It looks like the stock one... yes, no, maybe? http://minneapolis.craigslist.org/pts/630125998.html
i've got a triple gauge setup like these http://cgi.ebay.com/ebaymotors/02-07-SUBARU-WRX-TRIPLE-GAUGE-POD-3-BLK-7-GAUGES-03_W0QQcmdZViewItemQQcategoryZ43952QQihZ017QQitemZ270225084494QQrdZ1QQsspagenameZWDVW $80 for all three plus the mounting cluster. I've also got a clock mount if you'd rather use that than the pillar mount. the gauges work great. i've just decided to go gaugeless.
maybe... im thinking about putting gauges by the other gauges. Don't really want people to know i have them. For now looking for turbo gauge to install where subaru has the stock one.
you can use any wires, just need to splice into a power source, and you can get a vacuum line for super cheap at parts store. where are you located? i could help with the install if needed
IIRC the stock boost gauge is mechanical so the only two wires are needed to hook up: illumination and dimming (violet and orange wires).
You'll still need the vacuum line, that is a definite. Just the electrical wires that must be connected are different between a mechanical and electrical gauge.