I drove a 2015 Challenger R/T Scat Pack, I believe it has a 12.3:1 ratio, and even that was very nice. I wonder if 10:1 may be too fast...? Does it make the car harder to turn if it has a higher ratio (may be a stupid question but I'm new to suspension and steering)?

As for the gears, what ratio would be better for a GV?

I haven't decided on the tires, I don't even have the car yet. I'm in the process of building up the cash to buy the car, and I'm planning out the build in advance so that I know exactly what to do and what to buy once I have it. What size tires would be ideal for a good mix of speed and handling, and to accomodate 17" or 18" wheels?