Exhaust Smoke Question

[Scotty_Boxter_S]

I have only had my Boxter S for 2 days, yesterday when I was out and about, I ran it for about 30 mins to let it heat up, then started to give it some boot, to my dismay when I passed a Car there was a large white cloud of smoke once I eased off the accelorator.

what could cause this??

the car has barely been used for 1 year, has 37,000 miles and seems to run fine apart from the worrying smoke.

thanks
Scott.