I think your best source of info would be the Ford Australia Forums as there are all sorts of Fords over there with various mods. But if you think about the basic combustion engine principle of more air in and and more air out equals more horsepower then it's simple. If you want cheap and don't want forced induction then I'd say cold air intake with filter, pacemaker headers with exhaust to start with. Then when funds permit port and polish head, fit some cams and a Nitrous Kit. Benny