Advan RZ in 18x8 has a MSRP of $660/ea. There may be a little room to work, however I would need for you to stop into one of our stores to give you a defined quote.
I would recommend the Falken RT615 for a good performing summer tire. In 225/40/18, they would run $135/ea (includes shipping to us).
*Mounting and balancing would be $65 for the set
**Lug nuts to fit that particular wheel would range from $45-$120 (depending on the style you would prefer)
Jason Christopherson
Store Manager
Tintmasters
Fargo, ND
(701)239-8468