Well I would not know about your car but I do know the spare I purchased will fit my RT because the spare wheel has a 20 inch rim. Maybe you will have to get the spacers that are available with the aftermarket 500.00 wheel kit that is being sold that require the spacers.
I don't worry about a spare I have the tire repair kit in the trunk and if a tire is not repairable I call an 800 number and have a roll back pick it up and haul it in.
Who has time to twiddle their thumbs, wait for a flat bed, wait for a replacement tire, or find another ride home, and get a ride to pick up their car once a tire is installed. I don't even go to the dealer for most things even warranty, if it's less trouble to fix it myself. With a spare, 15 minutes you are back on your way.
The 2009 SRTs only had 4-piston Brembos in the front. The Chrysler 300 came in four models- Touring, Touring L, S and C. Only the 300C had Brembos.