
And the surprise looks like this:

370bhp stock, with over 400 easily available with a pulley upgrade and more aggressive mapping. I'm also lucky enough that the car is registered 4 months before it would be legally required to have catalytic converters, so that should free up a few more horses too.
I've also heard that Aston Martin exhaust manifolds add 30bhp. If the stock ones are that restrictive I can see myself making up some tubular ones- I'm never happier than when I've got a welder in my hand!