Adding an exhaust to my "04 GT" and was considering the SLP Loudmouth II but I am also considering Borla. Not sure if I want to pay the extra $$ for the Borla? Also should I do the headers at the same time the exhaust is being done ? I am also putting in 3.73 gears and I have a fellow stanger who will do it for $200 is that about right ? Should I get it retuned after the gears are installed even if it's a manual ?