Probably a stupid question, but here goes:

What are the pigtails that are offered with HP tuners for? I see you have an option to order more than one.

 

Its for the wideband sensor +/- 5v. You can also set it to open a circuit once a condition is met. Basically you would want one for each car that you tune on a "regular" basis

 

Thanks alot. Exactly what I needed to know.

 

The connector for those analog inputs. You could
"connectorize" the car, maybe not such a bad idea,
and might want a loose spare or two. They sell them
for less than you can get the body and pins for, from
Digi-Key (let alone wire and effort) so you might as
well get a couple.