Both of mine do the same thing, but once warm all is good. Just let it warm up a little on a cold start, and when you take off dont push it until the engine warms up (i.e needle isnt on "C").
EDIT: I see your the guy that bought Brendans little beast. Congrats champ! you picked up an awesome car Got any plans for it?
Yeah thanks mate. Regarding plans for it - getting the f*ing thing to pass rego would be a good start !
Re: the shudder. I never drive the car hard or rev it right out when the engine is cold, I wait until it is well over the 'C'. Problem is that the shudder happens even at low revs and accelerating lightly.