Very bad shudder only when trying to take off.

Now i have a bigger problem and need help ASAP, seems like my first GTI is turning out to be a nightmare. It starts and revs clean to the red line when in netural but when i put it in gear and try to take off the whole car starts to shudder very very badly and just wont get moving, the clutch is still feeling normal at the pedal and is still taking at the half way point. when the car is in motion it goes just fine and smooth through all gears but if i have to stop on even the smallest hill it will jus shudder really bad and refuse to go, and i just changed front and rear engine mountings. Any advise will be much appricated. many thanx, shane.