>>558230
https://en.wikipedia.org/wiki/Blackburn_Buccaneer
It wouldn't need too much modification to turn the (very) high speed, (very) low altitude maritime/nuclear strike aircraft into an excellent CAS/SEAD platform. Although, if you're looking for a more radical overhaul take the old DeHaviland Mosquito from ww2 and you could turn it into an amazing COIN aircraft with modern engines, polymer hull, updated electronics etc. As COIN doesn't need particularly expensive weapons you wouldn't need to do much work to the payload, just update the 4 20mm cannons in the nose and swap out the bombs on the wing for a set of FFAR equivalent rocket pod.