You need a car that it doesn't matter (too much) if you smash up completely in the name of having a laugh.
It needs to have an exhaust quieter than about 98db.
It needs to look like it's not going to fall to pieces when you push it, or leak oil over the track.
I'd suggest taking as much as possible out of your car, if it's your daily - seats, spare wheel, other people etc - you'll notice a difference.
You want to take the MK4 8v around a track ?
He really can take anything he wants and odds on, if he's got balls he'll overtake over-protective Golf5 drivers trying not to murder their more expensive tyres and brakes, or put a lot more ££'s worth of car into a barrier.