Literally put in some Pioneer 4 ways yesterday. Night and day in clarity and performance even with the original head unit. Each door took maybe 45 min, with hand tools.
There are some great photos of others who did the job on here if you search "speaker installation."
2013 GT Base GHIG Track Pack + Recaros + GT500 AxleBacks + Boss 302 Tranny Cooler + Ford Racing Pro-Calibration