I have an 03 protege 5. first off, I have decided to go with forced air induction as my weapon of choice, nothing too big.
I'm starting off with the simple mods first, considering upgrading to mp3 ecu. What can I expect from this as far as yield, effect on mpg, etc? Will I forever have a check engine light? Is this a better mod than getting a chip? Also, is this a good idea if I plan on adding a small turbo?

 

the mp3 ecu is a good option if you plan on not going turbo. if you plan on going turbo, you might as well go with a mazda speed protege ecu.