I have a fast efi on my boat. I must say its 10 times better than carbs. I don't have any issues with the wide bad 02 so I don't know what gt is talking about.Closed loop is way better, aka full sequential than open loop. you cant run water in your exhaust tho. Personally its the best way to go to get the maxim performance out of all motors. It can do things a carb motor and mechanical fi can only dream of. Its is very pricy. I think I spent around $5000 for the ecu, wire harness, fast duel sync dizzy, fuel pump,reg, and injectors. There was a ton of other things I had to buy as well. It is a very complicated system to tune So have a professional tune it if you don't know how. The great thing is once you have it tuned you never have to touch it again, turn key and no maintainence unlike carbs. I can ramble on for ever about EFI. if you have any questions let me know. Ive learned everything there is to know about fast xfi in a bbc jet boat. EFI, Also known to others as fuel infection.