Thank you all. Although there is lots of information about exhausts, there is not too much about the sound levels....
I would love, just love, to able to walk in and demand the Akarapovic system, but the car itself was stretching finances enough.
I was really after a cheaper alternative, but have that old mantra 'buy cheap buy twice' ringing in my ears.
The cheap chinese ones may be okay, but the first I will know about it being too loud is when i get refused entry to a track day. I will look into the others mentioned here.