bro..dont waste your money on fuel savers and all those marketing junk..
btw whats yoru car bro?single carb/vtec/dual carb?and whats your fuel consumption?
even i had an eg8 vtec which did 7.5-8 km/l and then got it tamed to do 10km/l+
since its an eg8 i assume you have a beat barrel!if so try removing it and instal a stock exhaust /performance exhaust. because beats gain an additional 0.5-1 km reduction on the mileage!
take it to a good tuner and tune it well regularly ,change the sparks and all recommended parts if needed.
change your driving habits!i know its insane advice a stereotypical eg8 driver not to REV but if you control the unnecessary revs and braking you could save loads,
last but not least remove all excess weight from the car!a heavy car is always greedy on fuel
goodluck!