ETKA states the O ring for the MAF housing to be 79mm, so its probably a 3" type housing like we had on the KO4 engined 1.8t 20 valves - 225tt/S3 etc, and the picture shows what looks like a MAF housing from aforementioned 1.8Ts, so you may be able to find something on ebay off a 20v and make your sensor fit somehow?