Racepak offers their Universal Sensor Module [USM] which adds four sensor channels, each of which can be configured for analog or digital signals.
You can get throttle position direct from the TPS on any car that has a true TPS. You can pick up you brake switch for a brake on-off channel, or add any 0-5V brake pressure sensor. You can use a cost effective GM temperature sensor for oil temp [the software includes calibration curves for the GM sensors] and any 0-5V pressure sensors.
You could even connect it to a fuel tank potentiometer for constant readings of fuel levels!
You can also connect a second USM for four more channels, or use any VNet sensor, or do both. The system is very flexible.