The pro hardware adds standalone datalogging capabilities(no laptop needed) as well as 4 analog inputs & 2 outputs.

LC1 widebands go for as low as $200 and go up from there depending on the features.

 

OK what do you mean by analog inputs and outputs? That is cool that you dont need a laptop (I do have one though) Im not sure about the wb o2's why would there be so many different ones with so many different options?

Thanks Dave

 

What does the MPVI Pro interface allow me to do over the Standard Version?
With our Pro interface, you can integrate 0-5v signals from various sensors such as EGT, Wide Band, fuel pressure and others right into our scanner. You will have real time data from those sensors right next to your standard scan tool data such as TPS, RPM, MPH, etc.

Taken from here http://www.hptuners.com/forum/showthread.php?t=2924

A ton of info on widebands, who sells them and why they differ in price is found here http://www.hptuners.com/forum/showthread.php?t=5059

Things like displays vs. non displays, gauges, etc. play into things not to mention accuracy