there are 3 (possibly 4) different types of VAG CH style wheels:
1. Edition 30 Pescaras 18x7.5 ET51
2. VW Accessories "Rockingham" wheels, although I am unclear how they differ with Pescaras 18x7.5 ET51
3. Audi 14 Spoke S-Line wheels (A3 only) 18x7.5 ET54
4. Audi 14 spoke S-Line wheels (A4 only in UK markets, possibly A6 as well in others) 18x8 ET43
all of the above have interchangable centre caps (but will NOT fit BBS centre caps) and they all fit the Mk5 with no need for new bolts or anything else. to my eyes they ALL look silver, tho the Ed30 versions are apparently a smoked chrome colour.
Aftermarket you have the BBS VZ. these are 18x8 ET44. they also are a straight fit onto the Mk5 with no need for new bolts, but they only accept the BBS centre caps. the VZs were previously available in Titanium, but due to paint issues the current batch are silver only
the OEM 225/40R18 tyres will fit on all of the above with no issues whatsoever. they don't look stretched.
for my money, VZs are the only ones to have. they have the looks of the A4 ones, but are 2kg lighter EACH. they are about 1kg lighter each than the Mk5/A3 versions too. plus you'll get them brand new whereas all the others are either £1400 new from a dealer or 2nd hand only.