hey guys, i need ya'll help. i have a g35 2006 black leather stock.

i want to get the rims and tires changed and i have a few questions on that.
i think my rims are 18 but if i would want to get 19s or 20s do i have to do extra on the car? or can i just buy the wheels and rims and install?

also i wanted to ask what are the type of tires that are very "skinny" on the rims??

my tires now are pretty "thick" and i see a lot of sweet g35s with skinny tires on their rims. makes it look way better. any suggestions on tires that i can use to make it look that way??

i'd appreciate a answer from anyone! just trying to learn my way!