What function does an empty, plastic box serve in purification of emissions? Considering it comes before the filter, before any combustion, and - here's the kicker - the T5 engine has no such assembly? It's a muffling mechanism, serving no "polluting" purpose.
It's a "California doesn't allow you to modify your car" thing, right? Not a "I can't pass the smog test" thing in the typical sense? In a fully functioning car I don't think modifying your intake would ever effect the emissions. If your MAF sensor wasn't working properly or you had leaks somewhere then I could see the engine running too lean/rich causing emissions issues.
