well it would prob take 1 to 2 gallons of the stuff, its not as high quality as the 2 part line-X tarheel sprays, herculiner is still pretty good, only thing I wouldn't do it in is the bed, hah funny they say thats what its for. it does quiet it down a bit. Id have to look up the cost again on the bed liner I thinking I could do it for around $150-200. If you get the seats too id be glad to help you fit them if you have your old bench seat brackets to weld too.
definatly want to go show off my jeep next time autoshow rolls around, we should get all the MJs around and have a nice little section, that would be sick. be something different too.