All good questions Venthos. (Thanks for the PM)
I apologize in advance for the limited information I have. Our winter options will not show on the web until the end of this month/ beginning of Sept. Also, the exact fitment info for this car has not been added yet to our fitment guide so I am going to make some assumptions based on the Charger. We hope to have the vehicle in our guide shortly.
For a situation like this, I find its better to locate a wheel first then search for a tire because its going to be harder to find a wheel that fits the criteria than a tire. (neither will be that easy though) Our guide shows that you can run 18" wheels on the SRT8 version of the charger. Not any 18" though. You are correct that it has to be a wheel with a large enough "x=Factor" (term for brake clearance/ curve of the back of a wheels spoke) to clear the Brembos. I do show a few wheels in 18" that will work on the vehicle but although they can be used in the winter they aren't dedicated to winter use and therefor may not have a durable enough finish for full time winter use. (especially on salted roads).
A few 18" wheels that clear the Brembos on the SRT8 Charger
MB Tucson
Akuza Creation Black
*There are a few others but they are Chrome.
I will have our wheel department look for some more wheels options for this. There may be a steel wheel option.
If you are willing to spend the money and you find a wheel you like that isn't a dedicated winter wheel, there are some clear powder coats out now that can be applied to strengthen the wheels finish. (Call your local powdercoater for prices and details.)
As for tires, again, if the Challenger is set up similar to the Charger a 225-60/18 or a 235/60-18 tire would be great for a winter size. There are a number of tire manufactures that build snow tires in these sizes. (these will show on our web site at the beginning of September as well)
