i cant report mpg. but i can say i've driven both in a super cab 4x4 and the differance is vey noticable.

the 3:73s will still roast the tires off a stop light if you arent careful, but the 4:30s are downright awsome! throws you back in the seat pretty good. i'd say if it was me i'd go with the 4:30s just for the fun factor. but the fact you will tow i'd say go with them.