adding a pod filter & doing extractors will increase power but will also most likely improve your fuel economy under normal use as the engine will flow better as it isn't as restricted. I don't know too much about rice burners, does it have an air flow meter or map sensor? a map sensor will be fine but i did have a gtx familia that kept blowing air flow meters after i added a pod filter. an air flow meter lets the right amount of air mix with the fuel. a map sensor adds the right amount of fuel to the air which simply means more air, more fuel & therefore more power.
I don't agree that modifications decrease the value on this type of vehicle, if it was collectable it would.