They keep you warm and quiet? (8)
I believe the answer is:
mufflers
'they keep you' is the definition.
The definition suggests an adverb but the answer is not.
'warm and quiet?' is the wordplay.
'warm' becomes 'rs' (I am not sure about this - if you are sure you should believe this answer much more).
'and' means one lot of letters go next to another.
'quiet?' becomes 'muffle' (I've seen this before).
'rs' put after 'muffle' is 'MUFFLERS'.
Can you help me to learn more?
(Other definitions for mufflers that I've seen before include "those protecting deep throat?" , "They keep one warm - or quiet?" , "They suppress reports in the US" , "Scarfs or car silencers" , "Scarves or silencers" .)