Boy, having jumped from pre-computer age cars right square into the middle of totally computer controlled cars, I am sure having to learn a lot! I see all kinds of hand held "tuners" for sale, usually together with CAI systems and modified or larger MAF devices. What exactly does a tuner do to the car? I assume that it reprograms the engine control unit to allow the engine to exit the bounds of smog control settings and releases max engine power potential? And I assumer that this is where the term "tuner cars" came from? It appears that an N/A car can add about 35 HP through the use of these devices which would be neat. But will the car then pass emission control tests?