I would disagree with that statement. A 2.25 inch system on a 1.8 litre 1ZZ is more than enough. I agree with DJKOR, just so you ALL know and understand this: Standard 1zz-FE Exhaust piping is 1.75" - Peeshooter size The Sportivo (2zz-GE) Exhaust is 2.25" - a very good upgrade from the standard 1zz exhaust. The next option is a 2.5" catback exhaust, which WILL reduce preformance on a 1zz, if there isn't any mods to support this size exhaust. (eg. CAI and headers) On a Sportivo, very good mod. and of course, get 3" piping ONLY if running forced induction or upgraded ECU. My 2c Evo well said. i dont think anyone even has a 3" setup on their 2zz... thats NA.