how do you unlock the bonus cars (camaro, BMW)in MWBlackEd.?

[pspcow]

I've beat #68 challenge but all I got was a shiny black Mercedes(I think..).

[peterfaj]

You mean that blue-silver BMW M3? You get it by finishing career.

[RedCarDriver]

ShopSpezial or hexediting, I guess. The Camaro is only available if you have the Black Edition or a mod to emulate it (or something), though.

[Striker94]

If you have MW on PC, there's a few saved games on this site that have been edited so that you can get the bonus cars for close to nothing, plus a black edition patch...