Yep, i'm inclined to agree with Toobs here - the reduced boost while cold, and it's relation back to the computer, and the current condition on the motor. I'd be interested to know if a "Carbon Clean" would improve the situation - I've seen many cars with minor stutters and shudders have their problem resolved with this being done?
Excuse my ignorance, but what's a Carbon Clean?
Motor has done 137,xxx and has been regularly serviced so should be in good condition. Also the intercooler and exhaust were replaced about 3 years ago. The throttle body was also cleaned at that time.