[weq92f]

There is a nifty little device available for about 100 bucks that measures all of the parameters and allows you to put it on the vehicle to effectively model your choice on the car.

I would call around to the wheel shops in your area to see if anybody has one of these and will allow you to utilize it for your needs.

Basically you attach it to your hub and then place the 'tire contact' patch thingy wherever you want it in your wheel well. When you're happy, take the measurements and then order your wheels.

-klb