[smashedheadcat]

The Dynojet Wide Band commander is worth it. It's more accurate than what you're going to get a most dynos. It uses the same sensor most shops use, but you have it installed in an o2 bung that you weld in before the cats. This gives you a more accurate reading. The WBC also has a datalogging feature, a programable warning light (can come on if leaner than say 12.0 to 1 a/f at 80% throttle or higher etc). It can also be configured to plug into the computer at the dyno facility. So you can use your sensor to tune with and not the old sensor stuffed in the tailpipe of every car that comes through for tuning.

Now, some dyno operators keep their sensor fresh and up to date so you don't have anything to worry about. But, having the wbc allows you to monitor the a/f ratio in real time, out on the street. So if any problems ever arise, you'll know about it.