Here are two sites w/ mods you can purchase. The first does not show a pic.
http://www.best1hobby.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=168&Product_Code=DM2351&Category_Code=autoaccessories
This i s a great site provided to my from these very forums. This is just one seat...you can click on products; detail sets; seats. They have 6 different seats you can chose from as well as a pretty good amount of other products. HTH
http://www.scaleautostyle.com/zeta.php