At the present time there are no mods for the 2003 1.8 liter to make it faster. Zero. Zip. Nada. The pulley kit will not work on it.
Kleemann is working on replacing the stock supercharger with a Lysholm supercharger which should give a big hp increase, but it will cost about $3000.
Kleemann is working on replacing the stock supercharger with a Lysholm supercharger which should give a big hp increase, but it will cost about $3000.