2013 370z new owner with questions

Todd Copeland

Just a couple of days ago I bought a slightly used 370z with 2500 miles on it. I love the car but after buying it from a Honda dealer, they told me that the exhuast had been upgraded and some other things too....
They gave me the original exhaust and parts along with a dyno run from slowmotionmotorsports.com which says rc2 intake, cat delete, can't exhaust up-rev tuned max 305 who/235wtq
They gave me the complete stock exhuast and two coil springs. They told my dad when he picked this stuff up that the springs were part of the "airbag" system....
Clearly this doesn't refer to the airbag safety system....more likely suspension and I did notice today that the rear wheels have a slight cant to them looking at the from behind. This bothers me but the car drives great and the car fax shows no damage history.
I am interested in knowing more about these modifications if anyone can help. Thanks.