I got my mk4 back from Castle Hill Exhausts on Monday - Great job - great price. I got a 3" turbo back exhaust with 100cell cat and rear resonator - and it's great - damn loud - but I asked for that..... ha ha I would recommend you talk to dave - his email address is sales@castlehillexhaust.com.au

I think what they are talking about is aluminiumized mild steel - nothing wrong with it IMHO - I don't like stainless steel as it tends to be brittle and make the sound more tinnie - I prefer mild steel even though it is heavier.

Ring or email Dave and ask him.

My whole job was done in 5 hours - very impressed