Being in my early 50's and having a hard time catching even 5 hours of sleep a night, taking naps in the car during lunch in the parking lot or napping at security guarded rest stops during long trips is to me a MUST for a well rounded vehicle. I don't know about you guys but my car and the road is like a second home to me. I used to sleep in a pup tent for three years in my 20's so I can easily nap in a Mustang provided the seats fully recline. Be that as it may I was glad someone answered me on the 4.6 forum and gave me the answer to fully reclining model '99 to 2004 Mustang seats without spending a penny:
http://mustangworld.com/ourpics/fcar/recline.htm
Woohoo!!!
Still I never got an answer on the 2005 model, which I was considering to trade my GT for but it doesn't matter now, since I really love my 2003 much, much more. Plan to make the modification today.