This is not a success story. Recently I got a set of pretty good looking 6 x 14" ATS wheels for the Alfa 108 mm bolt-hole circle. The wheel offset was ET 38 mm - corresponding to the original Alfa 105 size. 10 mm spacers at the front and 30 mm (!) spacers each side at the rear were no problem.
Tyres were Continental Sport Contact 185/70 R14. These wheels gave the GT junior a distinctive "German Look" of the early seventies. Unfortunately these tires offered a very good ride comfort but no sporty driving properties.
The wheels had a lateral and radial run-out of more than 2 mm. This lead to tremendous vibrations at speeds between 80 an 120 km/h. As a result I graded up to 15" wheels or use the standard 14" steel wheels with inox Alfa hub caps.