Carb Swap Weber/Mikuni

Anybody swap out the Mikuni carb for a Weber replacement type? I have a 88 2.6 that is getting 11MPG and am looking to put the weber replacement on but wanted to see if it's worth it first.

Swapped out the 11MPG A/T carb for a known good carb off a M/T with A/C will see how that one works.
Still would like to know what to expect from a Weber carb from someone that is using one, mileage wise? Anybody?