How exhilarating to go flat out for stunt (7)
I believe the answer is:
wheelie
'flat out for stunt' is the definition.
The definition suggests a singular noun which matches the answer.
'how exhilarating to go' is the wordplay.
'how exhilarating' becomes 'ie' (I can't explain this - if you can you should give a lot more credence to this answer).
'to' means one lot of letters go next to another (I've seen this in other clues).
'go' becomes 'wheel' (wheeling is a kind of going).
'ie' after 'wheel' is 'WHEELIE'.
Can you help me to learn more?
(Other definitions for wheelie that I've seen before include "A bicycle trick and a bin" , "dangerous move on bike?" , "Biker's stunt" , "Manoeuvre" , "Type of bin" .)