Keep seeing this in some awards/posts by Mike whatsit - what is this and whats it do that the orig equip doesn't?

FROZZTY

 

SHIZZLE, think of it as the opposite to the exhaust. It allows the air to flow into the chamber for firing.

From the little I know the Evo one has been bored (and polished)out thus allowing more air through. More fuel = theoretically more power.

As always

INJECTOR

 

Direct Link

Not sure if its a good stand alone mod, you would really need to combine it to see gains IMHO.