necessary gauges

what are some necessary gauges to add when installing a turbo application???

boost gauge, oil temp and af ratio

exhaust gas temperature gauge is good to have also

egt, boost, oil pressure

EGT is very nice because you don't want to cut the car off while the turbo is still hot. A turbo timing is a very nice extra. If you're not familier with them, baiscally when you park your car you can take the key out of the ignition, get out, lock the door, turn on the alarm and walk away. The turbo timer will keep the engine idling until the turbo has cooled down then shut off the engine.

I would also have a A/F ratio guage just because I'm a little paranoid and things not can, do, go very, very, wrong if you lean out with FI for whatever reason.

Boost. Hey its cool to watch. Spend that much money on a turbo you deserve a cool gadget. :)

Oil pressure is good. Oil and coolant tempatures are also nice to keep an eye on things especially on a hot day with a stock radiator/no oil cooler.