Given the choice, I would use BAR-OIS. As I've said before, it is easier for me to do tests and run my shop. Before OIS I hardly ever failed a 2000 or newer car for tail pipe readings that had the cat monitor complete. I can't see gearing a program to go after 1/100 of a %
I don't think I have ever failed a 2007 Silverado for NOx.
I've hit rock bottom but I brought a pick and a shovel and I'm ready to dig!
The TRUTH, you can't handle the truth! (Jack Nicolson don't ya know!) The truth is OIS is just in time that NO ONE finds out the scam. By the time we realize the increase in HC and NOX we will have another system to loot the public with and plenty of scientists and politicians to back them up. Hell we might have hydrogen cars or electric cars with a decent range.
From my point of view, tailpipe test is the only way to truly find the polluting vehicles. That being said, from a convenience and efficiency factor (and screw mother earth) the state approved clean pipe OIS system is the way to go.