If you are not versed in the black voodoo arts of tuning carbs by ear, taste, smell and other mumbo-jumbo you will find an a/f meter beneficial in helping get the best power and economy out of your engine. The only 'hard' thing is that you'll have to have a bung welded in your exhaust system. I put an A/F meter in my 122 when I was putting in a new exhaust system, so it was just a matter of taking the pipe to a welder. More of a PITA if you're welding it into an installed exhaust, though certainly not impossible. I had mine mounted a bit downstream from where the y-pipe when from 2 to 1. The rest of the installation is simple wiring. They are more expensive, but I think you'll find a wide-band sensor/meter more useful. I think the brand I got was AEM, from Summit Racing.