What is a good afr gauge and and O2 sensor kit?

we run the NGK

Same here

I noticed that those are not a gauge. Do you leave them installed all the time?
Also is it worth having a gauge on the dash or am I better off with a one time tune with the NGK?

Not sure if you're looking for a permanent installation or handheld for tuning, but I just ordered the Innovate handheld. If you wait a couple days I can let you know what I think of it.

I've been very happy with the MTX-L gauge / sensor kit from Innovate. I use it full time with the gauge mounted at the helm.

Good question. I've been thinking about changing out two gauges on my helm for AFRs. Gauges are cheap and lean is expensive.

I seen that the NGK is discontinued. this appears to be the replacement. Any feed back? Does it display the same results?

http://www.ebay.com/itm/Ballenger-Mo...item3ce6a3bd58

I have had great luck with the Innovative MTX-L ... All in one kit priced reasonable. http://www.amazon.com/Innovate-Motor...novative+MTX-L

Innovate just came out with a dual channel AFR setup. One gauge that reads and displays two wide band sensors. Great space saver for those who want to monitor both exhaust banks.