Been measuring the Vento cups up today for some centre caps. The stock speedlines are 58mm I believe and the Vento cups centre caps are 1-2mm wider diameter.
I believe the centre caps from a Speedline Corse will fit and advertised as 59mm-60mm. Im going to test fit one. Link below
Renwart will is making me some VW Motor Sport 3d printed Motor caps in black and light grey same a stock MK3 Rallye prototype that i will adhesive on to the corse speedline cap after testing fit. He has estimated between 30- 40 euro. Example of his work below and also a diagram of the Speedline corse centre cap.. Have asked Ren to make the decal 3d print in 55mm. to compensate for the diameter border. Also attached below picture of Motor Sport cap. Once made not sure whether to preserve them and only put them on for shows.
Can be seen on video if freeze at 0.50/1