The 1099-misc from the car manufacturer is personal "other income", under a special rule for "SPIFFs"* and goes on line 21 of from 1040.
*SPIFF (Special Performance Incentives for Field Force) payments reported on Form 1099MISC; (1) are not treated as wages, (2) are not subject to federal income tax withholding, social security, Medicare, or federal unemployment tax, and (3) are not considered to be self employment income and, therefore, are not subject to self employment tax. Box 3 of the 1099-misc is the correct place for a SPIFF to be reported.
http://www.irs.gov/pub/irs-pdf/p3204.pdf
