From what I understand, the CDC shaker kits for the mustangs are even easier to install than on the F150s... My F150 had a support bracket that had to be trimmed up a little bit to get the weather stripping to fit... The mustang supports are actually just outside where the cutout goes for the shaker kit...
A deal pops up once in a while on Ebay. Check out seller "MustangMods" Thats where I got mine for the truck. I stole it for way way way way less than retail
(On a side note, in the last month I have watched 2 Roush SiDo exhaust catback kits for the 04-08 F150 sell for under $300 from that seller)