rim help
 

So I know just about nothing when it comes to rims other than Id like a new set and need some help.

Our cars stock have wider rims in the back than the fronts. those of you that bought third party rims did you mimic this setup and how do you do that on tirerack.com? when I go to the site and look at a set of rims they seem to only list one size per rim and its usually the front rim.

I like oz's ultraleggera rims, I've also read the descriptions of what offset and backspacing mean but I can't visualize this on my car bc I have no idea what the stock rims specs are. When I say stock im refering to the non sports package.
Offset: 35mm
Backspacing: 5.91"
Bolt Pattern: 5-114
Rec. Tire Size: 225/50-18
Weight: 18.4lbs.

oh yeah forgot to mention it would be ideal to match the current tire size so I can use those tires on the new rims. not sure if this is doable.

sooo no one out there can give me any advice on how to shop for wheels?