ae gauges - where to connect?

[allensteiner]

i found a sweet single din, 3 hole gauge pod on ebay that'll fit the pocket under my stereo. i want to hook up gauges like iat, volt meter and transmission temp.

now, i now how to hook up the volt meter - simple.

but can i splice in the iat gauge to the stock iat or does the ecu somehow converts the info from that into temp? would i need a separate iat sensor to work with the gauge?

the transmission temp gauge - do i just hook it up to a sensor that i'd have to mount in the at fluid pan or somewhere else? i'd like to be as close to "true" transmission temp as possible.

and in the future i'll do gauges like oil pressure, oil temp etc.

edit: also can i splice in a water temp gauge into the existing sensor harness?