Most people go for the AEM one. If you know what your target AFR's should be, then a simple innovate one will do. http://www.ebay.co.uk/itm/INNOVATE-DB-BLUE-LED-WIDEBAND-AFR-GAUGE-3793-/290874376359?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item43b976c0a7#ht_3078wt_993