thining about it , its not really a shake more of a vibration, and all my car vibrates 
it feels a lot worse sitting in the drivers seat than the looking through the bonnet and trying find out what,
as anyone ever had there downpipe crack near the spring bit,( i cant see that it has by the way) i'm just wondering if there was a crack a drone from that could be causing vibrations?
cheers
Stick your hand down there after you have turned the car on (not when it's hot), and if it is blowing you will feel the gas escaping.
To be honest this problem doens't sound like it is connected to your exhaust. My money is on a vacuum leak, this would also account for the shaking/vibration when you start the engine from cold as the leak will be leaning out the mixture for cold start enrichment.
