brad1.8T

should fit under the rear (I've had 17x8 ET35) Under the front it will poke out around 20mm If you want to run 8.5" without poke you need ET50

Try Alba European in Moorooka. He's a really good diagnostician. My guess is either the PCV or separation of the rocker cover labrynth. Possibly oil control rings gummed up

If it's the reusable casing with replaceable filter then the plastic casing has probably hardened & cracked. It's fairly common. you can buy replacement plastic casings or aluminium ones. Why would you remove the radiator? At worst the fans would come out but I've never heard of that being needed.

I DIY'd the rear quarter panels, boot floor, spare wheel well and under the rear seat. It took a day including faffing about drinking beer, etc. It made a big enough difference that the noise from the front wheel arches became quite obvious. I wouldn't pay someone to do it unless you are really cashed up.

What are the front & rear settings it is on? Without some data it's impossible to say.

Yes they fit. I have a 2007 1.8tsi Elegance M6 Hatch. It has the following suspension parts: Golf GTI rear sway bar Audi S3 Alloy lower Control Arms and bushes Eibach Springs for an Octavia wagon Koni Yellows for a Golf GTI It works really well.

The hub carriers are ferrous. If you want alloy you need to fit Passat/Superb units. AudiTT Units also fit but require some additional parts. If you google the same swap for a Golf GTi you'll get the full information.

IIRC it's an M6x10. I just used a standard hex head with washers out of my "these might come in handy one day" can of fasteners. that ebay listing doesn't look right