25-30 horsepower (roughly 25 % increase) is out of the question with just bolt-on modifications to a 4-cylinder engine. If you were to install a quality cold air intake (we don't know what brand yours is, and there is a difference between some of em), a tube header and a properly sized exhaust, you'd be looking at about a 15 horsepower increase, max.

As for the resistors, Qtiger is right. I read up on that scam. Someone ordered 4 resistors for 4 seperate Honda cars, all the same type and trim (a civic or accord or some other, not sure). When the resistors arrived, he tested each one with an ohmmeter. These resistors, supposedly all for the same car, the same engine, and being installed in the same position, all registered different resistance values when tested. That showed pretty definitely that the resistors were just random units sold to make a quick buck to unsuspecting people. Don't put it in your car, there's no telling what a random resistance value will do to the ECM.