Hello,
Thank you for your message. As we don't have this sense on the French side, I'll pass it over to our FR base to see if
@Lacuzon would like to add it.
I don't quite understand your sentence by the way, I think you either mean:
Cars with spoilers are really expensive; or
Spoilers for cars are really expensive
(The spoiler's car would be the car that belongs to the spoiler, which doesn't make much sense.)