GUDE cylinder heads opinion

[CTScott]

I read an article on one of the Scion sites a while back and it does have the results that they claim, but to reach its full potential you need fuel management, so make sure you factor that into the cost. If I remember correctly the cost about $1800 + your head as a core. Add fuel management and installation to that and you are up in supercharger or turbo range. I would imagine as well that to take full advantage you would also need to upgrade the air intake and exhaust manifold to match the extra flow of the enhanced head.

If you want to add performance without having your California inspection issues, why not swap the engine to a Scion XD 2ZR-FE, which is the 1.8L offered in the Vitz in Japan. It would look stock and the XD ECM can be easily reprogrammed with your VIN, so that the ECM would even respond with the proper VIN.