Luggage item sauciest that vibrates (8)

I believe the answer is:

suitcase

I'm a little stuck... Click here to teach me more about this clue!

'luggage' is the definition.
(I know that suitcase is a type of luggage)

'item sauciest that vibrates' is the wordplay.
'sauciest' can be anagrammed to 'SUITCASE'.
But, I am not clear how this is indicated.

Can you help me to learn more?

(Other definitions for suitcase that I've seen before include "Travel bag" , "Piece of luggage" , "A bit of baggage" , "Type of holdall" , "Travel item (two legal terms!)" .)

I've seen this clue in The Sun.

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