I had engine oil/petrol smells when using the A/C on my S2 when I first got it. I was told that the insulation around the air intake on the top never seals well.
On a trip to Malvern I bought some extra sealant and placed a double height layer around the intake and this made a great difference to the interior smell.
I will get some pictures and post them to try and explain my ramblings.
Sorry I cannot comment on the boot smell, nothing in mine.
