The Eduard sets are long OOP, but if you want to search for them, the bomb bay was 48144, the exterior was 48145 and the interior was 48146.
The doors on the Monogram kit are solid (left and right) whereas the actual plane's bomb bay doors folded in half as they opened so the Eduard bomb bay set was a necessity.
If you got lucky and found all three sets, you'd probably end up paying around $10 a piece delivered ($30).
The landing gear tires are made very thin to allow them to retract into the wings. Resin replacement tires would cost around $5.
New resin engine, propeller, maybe the turret machine gun and the project is pushing $45-50.
But it's your time, money and hobby to do with as you please.