FB -
The B has 440 nm combat radius, versus 590 nm for the A. That's with internal fuel and 2 x 1000 lb JDAMs + 2 x AIM-120, (2000 lb bombs on the A), and it's HHHH versus HMMH.
The B has no internal gun.
Air combat performance will be affected by 3200 lbs greater OEW and somewhat smaller H-tails.