EDIT: I'm also at 100% everything with the collectors edition, but Isimply can't find the following cars: (ps2)
1969 Plymouth Road Runner
2006 Pontiac GTO+
2006 Chevrolet Camaro Concept*
Tier 1
2004 Lexus IS300
1986 Toyota Corolla GT-S (AE86)++
1992 Toyota MR2
2007 Audi R8/LeMans Quattro
2003 BMW M3 GTR
2006 Koenigsegg CCX*
2006 Pagani Zonda F**
2006 Porsche 911 GT3 RS