What your actually hearing are the camshaft lifters. The reason they click when cold is a majority of the oil has drained off of them. As the car warms up and oil is spread throughout the motor, the lifters quiet down.
Clicking sound on my coupe was diagnosed to be a bad belt. It was replaced by the ferrari/ maserati dealership at no charge. The car is running sweet. I have been very impressed by the quality and level of care by my dealership.
We have found that most of our cars get the lifter tick when they have been outside in the cold for a few hours. They will also do it if they have been sitting for a period of time as well (regardless of temp). Just letting them warm up always does the trick.
My 2002 coupe had this problem after any run for more than an hour or two. We have extremely long and hot summers where I live in Australia. Dealer replaced lifters under warranty which failed to solve problem then replaced std oil with 10w/60 and never had any problems since.