I bought the GP-meter 6.0 Air Fuel Ratio Display Kit to replace a Gunson Gas Analyser kit when tuning the carburettors on my classic Minis and Locust 7 kit car. I purchased a VW 5 wire Lambda sensor from ebay to go with the kit. As I will be using it on numerous vehicles with carburettors I decided to make up an exhaust probe with for the lambda sensor as detailed in the article on DTECs website (http://www.dtec.net.au/Lambda%20Meter%20Probe%20Design.htm).
I am really pleased with the end result it makes setting up the carbs easy the meter is very responsive.
The only thing to improve the kit would be an extra 3 way connector to use when wiring up a power supply. The kit comes with a 3 way male plug but I could not find a matching female socket.