Are there any toyota or scion models that have a cold air intake comapatible?
CAI won't do much unless you swap out the intake and exhaust manifolds, and do a major exhaust upgrade as well. You will actually get worse mileage as cooler air won't atomize the fuel as well. Don't believe the sales pitch. CAI's are one of the LAST tweaks to try and squeeze a few extra HP out onto dyno sheets. Biggest difference will be how well you get rid of the air BEHIND the engine IE exhaust, and how the engine is programmed (tuned). One of the best things you can do for the exhaust is get rid of the part where it has to snake over the rear suspension, and have a side discharge made under the rear passenger door. Hope this helps :)
Search Toyota Matrix Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Toyota Matrix Experts