it was cheaper and more effective to give the main cast members of Will and Grace a new Porsche, than pay for advertising in USA today

Both Friends and Will and Grace became huge hits when the network ran re-runs during the 2nd summer 

and they got more free publicity for getting the cars than an ad would have fetched.

But they were Porsche Boxsters, and Sean Hayes mentions he could barely pay his rent at the time, so he sold his right away because he needed the money. 

https://www.youtube.com/watch?v=aClXKgAuYNc