You must beat the Burger King challenge and as a reward you will receive every junkman part... I'm unsure if there are other ways to get it...
For career, you have to have already ultimate nitrous on a car to get it from a blacklist racer. In My Cars, if you complete the burger king challenge (by pressing up down left right up down left right at the "Press Start" screen to unlock), and install a pro super pro or ultimate nitrous. then go back and put on junkman.
It is Nitrous (Nitro).
you get all junkman parts
www.cheatcodes.com
There isn't a cheat for that. Only for unlimited nitrous and speedbreaker.
iammostwanted
yes but you have to buy it sometimes other times it's already on the cars.
yes
beat clarence razor callahan
Yes after yo beat razor
there is no code
Sorry but no