The LM1 from Innovative is the industry standard for the home/ hobbyist/ amature 'tuner'.
Forgot about the professional also. ;-)
I figured a professional would likely have a LM-2 or one of the many stacked data acquisition packages they and many others offer (at that point its deductable).
Anything from 1 O2 sensor per exhaust pipe, all the way up to a wideband for each exhaust port (tempreatures, pressures, engine speed, trans speed,volts, amps, throttle position, what would you like to know, for enough $$$ they can record it for ya).
Although, a wideband for each exhaust port on a 6 cyl engine w/ 4 exhuast ports looses a touch of accuracy in the 'translation'.
That all assumes you want onboard equipment, as opposed to stationary for a dyno (there's lots for that too).
