So what if we take a Scirocco with a 16-valve breathed lump in it - cams, head, carbs, high comp - running a manageable but conservative 200 bhp?
To actually make that car power-to-weight equivalent with a Golf championship car (say 160 brake, 156 per tonne), the Scirocco would need to weigh a heavily ballasted ~1280kgs.
Unrealistic, so alternatively, let's up the power on the Golf Championship car from 160 brake to say 180 = 176 per tonne. Still on k-jet, some headwork, but moderate, done to a budget, but enough (you say) to win races. Perhaps a £6k budget, since you advertised your MK2 Championship car at £5.5k?
The Scirocco would need to weigh 1135kgs to have power-to-weight equivalence.
We're talking about the amounts of lead that causes MSA scrutineers to halt proceedings... especially as I'd guess your brother's Scirocco starts off, with driver (no ballast), in the low 800 kgs range.
That's 300+ kgs of lead.
I ask, how can these cars ever run on a level playing field?