Hi Smiler, all depends on how much power you are looking for and how much money you want to spend.
A good start would be to change the fuel pump (Walbro), colder spark plugs (NGK) and a downpipe (either decatted or sports cat) and get the car remapped by the hand of God (AndyF)
After this you are talking a lot more money headers, turbo, uprated internal, FMIC .................