Need information for new wheels
 

I am looking at quite a few different wheels for my car and I had some questions that maybe someone could answer.

1. I am looking on sites and there are many numbers to check to match the wheels to my car number of lugnuts, spacing of them, width of rim, etc. Can anyone tell me exactly the numbers I need to match and which ones don't matter?

2. I am thinking about upgrading to 17" rims, I have 16" Ghetto golds now, is this a good idea? The tires I plan on throwing on the new rims are Bridgestone Potenza's if this helps at all.