My Sirio EVO III 5 port turbo will walk a 18TZ down on top end. I know this as i do alot of R&D on engines being a modifier. When it comes to TQ the 12 cant hang.. but top end the sirio is evil! Heres a shot of a TC3 of mine with my modified .12 sirio on it. The sirio had about 4-5 mph top speed over the 18TZ via radar gun on the same gearing.