Its called "up most good faith" its a clause on your insurance, basically if they can prove its b16b ie. pic of engine code and not b16a like on your chassis plate they wont pay you,
So the inland revenue dont go hunting for johny civic unless you bring attention then they will do you for revenue fraud and your insurance wont pay out a cent and you will get black listed and liyng to ins company is an criminal offence as it is.........