Even installing shorty headers, especially equal length will involve some good mechanical skill, and require relocation of some stock stuff like dipstick tubes or smog brackets.
Take it from someone who even has pretty good mechanical skills, some stuff on the 5.0 mustang is pretty hard to do cus of the tight packaging of the engine. For instance, I can pull the valve covers off my Chevy in 2 min without any tools cuz I have the T bar type hold down bolts, and no extra brackets or wires covering them up.
The Stang's valve covers took me 2-3 hours, had to pull the upper intake off, and that one little @#$@#$ bolt in the back for the support brace was fun. I'ts not all that bad, just that you need to be patient, and do things in the right order.
Don't get over your head, find a buddy to help you or pay a Mechanic to do it. I would imagine they would charge up to 10 hrs?? Not cheap
