http://www.ebay.co.uk/itm/Genuine-18-034-BBS-CH-Alloy-Wheels-A3-Quattro-5x112-5-/112499958418?_trksid=p2047675.l2557&ssPageName=STRK%3AMEBIDX%3AIT&nma=true&si=4g2mBYLd%2BYsyMZv7VZE%2B%2FYrR8Tg%3D&orig_cvip=true&rt=nc
these are the wheels I brought for my mk6 R but might be me but the whole where the centre cap is seems bigger? might just be the centre caps? will they fit
If you've already bought them, there's a simple and practical means of seeing if they'll fit..
But like the guys above have said - yes, they will. They're the correct PCD etc so will bolt straight on.
The only issue might be clearance between the wheel and brake caliper. Your mk6 R brake setup is a little chunkier than on a mk5 GTI or the A3 they came off, although plenty of people fit mk6 R / 8P S3 brakes to mk5 GTIs with standard wheels - in part due to the fact you can still run 99% of OEM wheels with them.
The et54 offset of the wheels you bought means they'll sit 3mm closer to the calipers than what is possibly the most common OEM wheel on this platform - 18x7.5 et51. Worst case scenario, some 10mm wheel spacers will give you loads of extra clearance should you actually need it, while keeping things flush in terms of fitment - things won't rub unless you go lower than 40mm or so with springs or coilies, and it'll arguably look nicer than what presumably will look quite 'tucked' at 7.5 et54.
In short, you'll be fine. There's a very slim chance you'll need spacers, but this would not create further issues. Hope this clears things up.