http://cbsa-asfc.gc.ca/trade-commerce/tariff-tarif/2014/01-99/ch87-2014-eng.pdf
here is the link for the Tariff codes for car parts, if you do have to pay duty and that would be rare, use this, always check before you import.
car parts are not on the watch list, however wheel rims are, you always need to verify what country the parts are made in, just cause you may own a German car doesn't mean the parts were made in Germany, if you bought the parts in the US doesn't mean they are US made.
just saying...... High value shipments (HVS) are mostly checked anything over $2500, Low Value shipments (LVS) below $2500 are not, Customs looks at description that is normally what triggers an inspection.
hope this helps