Standard, the 150's & 180's aren't that quick at all. Would get beat by:-
Pug 306 GTi-6/Rallye
Clio Williams/172/182
Civic Type R
Honda CRX (V-TEC)
Focus ST170 (vs 150) etc, etc.
& that's just in a straight line!
However, luckily, they can be re-mapped so they can reverse all of that.

150's > 200 bhp (approx.)
180's > 225 bhp (approx.)
Unfortunately, all of the above handle better than the Golf, so you'd have to look at handling mods as well. Anti roll-bar, suspension, etc