That said, I made some simulation based on real A3 speed recorded with several type of engine ans it seems that maximum real speed achievable with an A3 on flat road is:
300Hp => about 260km/h 160Mph
350Hp => about 270km/ 170Mph
400HP => about 280km/h 175Mph
To reach 300 real km/h 190Mph you will need about 600Hp!!!

So you'll need 1200 in a Golf.

Ok ok, the Golf is as aerodynamic as a van, but 650 should be enough.
Some magazines had HGP R32 BiTurbos measured in Nardo. I'll try to
finde one of them.