Right this may sound stupid for this time of year but anywho!
About a month ago i removed my air filter from my Mk4 2.slow gti and WHAT A DIFFERENCE!!!
Ive put it back in now but i am definatly investing in a K&N/PiperX air filter after christmas.
The main difference i noticed was the way the engine rev's, with the filter in it seems to have to drag the rev's up but filter out it is about 100 times smoother! Ive also changed my oil to a far high grade so think that has possibly helpped
