What you felt when you floored it was the traction control coming on, You can turn it off there's a switch for this its marked esp.
As far as your warranty the SRT6 doesn't have a 7/70, Chrysler as far as I know never offered it on the SRT6 only on the limited/base models.
And as for Mercedes honoring a Chrysler warrenty, that wont happen. they don't even want the crossfire in there dealerships parking lots. at least in Portland Or they don't.