I also had to drill, I had no holes, here's a picture:
http://imageshack.us/photo/my-images/183/montagespoiler.jpg/
http://imageshack.us/photo/my-images/183/montagespoiler.jpg/
I don't think my car had done to badly to be honest. Just came up against a golf 1.6 at the traffic lights and we had a little drag race down the dual carriage way. We were pretty matched up until about 60 when he pulled away but that's pretty good for a 1.0
When you fitted your engine breather filter could you start to hear more of a whining noise?
I think this looks pretty bad ass