Interesting, toll.no calculator says there's no toll on car parts, period. Wikipedia says there's no toll (customs fees) on EU goods other than food and beverages (which EU subsidises so they would be too cheap for Norwegian market otherwise)

Do you perhaps mean the 25% VAT? Most countries have that and it's not specific to imports. If I go to a grocery store and buy milk, that includes 22% VAT in the price. It's just that when you order from abroad, you may have to declare values and pay VAT and if the store you ordered from did a fuckup and paid VAT to their own country instead of declaring that they sold to Norway, you might get double taxed.