Cusser
+1y
Julian - I have a 1988 B2200, and I've had a Weber 32/36 DGEV on it for about 9 years. Mine's a Cab Plus, but before and after I still get 19 mpg. I'm really not aware of more power, but the Weber does run smoothly for me, even with AC, and with aftermarket cruise control.
With your mpg, and if you're not having carb issues, I'd stay stock unless you start having carb issues. That's why I swapped, my mechanic diagnosed ECU/carb issue so cheaper and less guessing for me to add Weber (but he may have been wrong, I also apparently had distributor ignitor and pickup issues then).