I was having problems with my S2 on boost where it was stuttering if you tried to give it some, i could only accelerate if i gradually pressed the pedal............................................. ...WELL ive just changed the plugs, dizzy cap and rotor arm and its goes well now NO stuttering and i can plant my right foot into the carpet with no problems !!! If anyone with a S2 has this problem change what ive changed set your plugs to .75mm as ford told me this figure and hopefully it will cure it !!!!

Hope this helps any S2 owners