I spoke to some of my friends.
The positive ones tell me, there is no reason why he wants to delay
your car and let your fark him or sue him.
The SE also want to process the papers and close the sales fast and
get his commission.
He knows that if you get rough, he have to sweet talk you and there
is a high chance I will demand compensation for late
delivery.
I still have my car to drive for now, as its is a one to one
handover when I get my new car, so its not too bad. 
The rest tell me...you know lah, make noise at their showroom, kao
beh kao bu, sue them, threaten cancel sales etc. Can do all that
lah...but end up everyone get sour and make my own name smelly. So
no point. 