In everyone's humble opinion...

What would be the best power boosting 'bolt on' (not swapping the engine) for a 90 Civic HB STD 1.5L 4SPD Manual??

You know a few extra HP here, a few extra there...just little things that will improve: power, efficiency, economy...anything. I basically like my car the way it is...I don't want drastic change...I just want to improve on what I've got.

Anyone?

Jason