Eduard Models has released a nifty photoetch set to upgrade the - already very nice - Hasegawa F-8E Crusader. This fret is of the no pre-painted style and that is good, because you want to paint the detailed parts and the PE parts at the same time.
The fret includes replacement engine exhaust “feathers” and actuators. Installing this part requires removing existing plastic from the original part, and you will need to bend a metal part to a circular shape. You might want to consider getting a piece of pipe or rod to be a template to shape the part to a circular form.
Other parts in the fret are meant to detail the landing gear struts and the landing gear well. Either by adding brake lines to the struts, or just general detail to the landing gear well and landing gear well covers.