NCIS S. 4, E. 14:

2005 Cadillac STS **
2002 Chevy Impala *
Kinda Ford **
2007 Mercedes S-Class (W221) *
1999 Olds Alero *

CSI:Miami S. 6, E. 10:

Hard to recognize but this is a 2004 Chrysler Crossfire that belongs to Duquesne. It appears in a few other episode, too. Thus at least **.
And this is a 2005 Dodge Magnum used for an assault at Duquesne. Though there´s already a Magnum listed I´d prefer this one since it´s a *** and better displayed.

The STS appears to be a 2006+ DTS actually. And the "kinda ford" is a Ford Econoline

The headlights of the Cadillac looked rather like STS than DTS. But I´m not sure. DTS is possible, too. I have no good shot of the front since it´s always too dark.

I'm nearly 100% sure it's a DTS