AFR guage

AEM Electronics Wideband Air/Fuel UEGO Gauge Kits 30-4110
Easy to install

Summit Racing
AEM Electronics Wideband Air/Fuel UEGO Gauge Kits 30-4110 $219.99

here is a ebay listing for it at $169.99. Summit will match the price.

AEM 30-4110 DIGITAL WIDEBAND UEGO CONTROLLER AIR FUEL RATIO KIT NEW BOSCH 4.9LSU | eBay