Originally Posted by Daviticus

As far as the fuel gauge, it may work pretty well. According to the FSM, on an S13 the fuel level sender's readings are as follows:

Full - 4-6 ohms
Half - 30-35 ohms
Empty - 80-84 ohms

And on a Honda [this is for a CRX, but almost all H-cars have the same reading]:

Full - 2 - 5 ohms
1/2 - 25.5 - 39.5 ohms
Empty - 105 - 110 ohms

As far as a temp reading, you could just use a Honda CTS and wire it directly to the cluster.

After that, you'd only have to deal with speedometer PPM [pulses per mile], but a Dakota Digital speedo converter box can handle that easily enough.