Sounds contented as a Manx cat getting out of a posh car (5)
I believe the answer is:
purrs
'sounds contented' is the definition.
(I've seen this in another clue)
'a manx cat getting out of a posh car' is the wordplay.
'a manx' means to remove the last letter (Manx cats have no tail).
'cat' becomes 'puss' (puss is a kind of cat).
'getting out of' indicates putting letters inside (to be outside something can mean to be around it).
'a posh car' becomes 'rr' (short for Rolls Royce).
'puss' with its final letter taken away is 'pus'.
'pus' enclosing 'rr' is 'PURRS'.
'as' acts as a link.
(Other definitions for purrs that I've seen before include "Cat sounds" , "Cats' noises" , "Feline sounds" , "Cats' contented sounds" .)