I have a brand new 18 inch BBS rear wheel for 4200 coupes. Probably also fits Spiders. It's the optional seven spoke item in Mercury Grey Maserati part number 199035. They are about £850 from Europarts inc vat. I'm looking for about £450. Pls e-mail me on peterjgriffiths@btinternet.com (pls note the "j" in the middle).
cheers
cheers