well high comp pistons are a must for n/a, dont go to high on compression or your car wont run on anything less than race gas thou. you should also get a very aggressive cam, but with that you have to upgrade springs and retainers, may as well go oversized valves, headwork is a must. the key to all motor cars is making all your mods work well with each other. really im going to be very blunt with you thou, if you are sticking with the d16a6 you may as well go turbo. if you swap motors to a b/k/h series then you can go all motor and have a sick ass car