cold air feed with air filter k&n,pipercross and a good manifold are the first options to do then following a full stainless steel exhaust.but still looking at 300-400 for exhaust.Got to remember weight wise depending which version you have.1.6 pulling 1150kg to 1250kg.Is alot of weight to pull.Some people try to lose weight on car ie removing air con,fly wheel up grade,lightweight wheels,back seat out etc.I think the fastest in the class is the 1.6i vtec s 0-60 i think in 9secs 1150kg.But i think thats down to the weight issue as being the lightest in its class.