Ok, I got my wheels and tires mounted up today, and I was told that they put Nitrogen (I think) in my tires... If i want to adjust my PSi do I have to use Nitrogen again or can i mix it with air at a gas station?

 

You should not have to add any PSI unless it was too low to begin with. The nitrogen is more stable and does not loose like the regular air. It also does not fluctuate in temp. as much. If you need more pressure I would use nitrogen again if possible.

 

ok, cool. and yes i think they are a bit low...

also, i have:
17x7 225/45zr17
17x8 255/40zr17

and I "got on it" yesterday and I think i heard it rub... i hit a small dip in the road and it bounced a bit...

 

If you fill tires with helium, it will lower the weigh of your car by 100#.

 

/ignore