Hi, im fairly new to this forum. I don't have a mustang yet but i am looking into getting one...I've been watching this forum to learn as much as i can about them. I am eyeballing an 87 GT right now. Unfortunately it has not been converted to MAF but it has an O/R H pipe with no cats and flowmaster 40s. I was told by a fairly intellectual friend of mine that having no cats with speed density can hinder drivability and/or fuel economy. Is there any truth to this?