Cheers to anyone who offered me any advice with regards to my plans to decat the car.
I decided to go ahead with it and Mr Greer fiddled with my pipes on Tuesday night and all seems to be in good order ready for mapping this weekend.
Yes it is a bit louder, but mostly in my head. Obviousy I'm not giving it any beans at all until its properly sorted. Got a very nice burble at tick over and I can hear that its going to sounds pretty special after the magic spell is cast by the wizard.
Fingers well and truly crossed. Will let you know how it goes.