So I'm planning on going to a local shop soon and throwing some Avant Garde M540's and RSRs on my car. My question is since it's a lease, would I be able to show up to the dealership to get its maintenance done with the wheels and springs on or would I have to pull up to the dealership with stock wheels and suspension?

 

The service people won't know if it's a lease or not. Unless you have a problem related to the rims or suspension, then everything warranty-related should be covered and you should have no problems having maintanence done at the dealer. Just put it back to stock when you return the car after the lease.

 

yeah, just at the end, turn it in stock (if you're going to turn it in)
sometimes the dealer will even take it back with those mods