Takes about 3 days.
Just got my C320 sport 4matic about 6 weeks ago. I'm in New Jersey so your timing may vary but it arrived in Maryland on a Monday and was ready for pickup that Thursday. Actually, I believe it was put on a truck that same day and driven to New Jersey immediately.
You will be so happy[

]with your new C.
My only recommendation is to tint the windows.
I agree with some of the other members on this forum about the window tinting. However, the Sport comes with a blue tint that is almost non-existant. I went with a 35% smoke tint on all windows and it looks great. It actually has a blueish tone to it so it looks like a custom color. Sampled the 50% tint but wasn't dark enough. Makes a big difference!
It's a very nice ride! Enjoy!