I have a 2003 Gt 5 speed Convertable mustang. Mostly stock. I am thinking 3.73's or 4:10s. Ive ridden in a gt with 4:10's before, with a few other mods, it pulled SOOOO much harder than mine, it was unreal, like driving 1 gear lower than what i do. His second felt like my first! He said his mpg only went down like 1-2 on the highway. Do you think 4:10's are to extreme. I dont do tons of highway driving, and my 5th gear is on Hellova overdrive.