if we had the 219 i would stop using the a20 as a bomber interceptor.

There are several planes in-game that can do the job better than the A-20.
If your talking about the He219 owl it was designed as a prue night fighter and nothing else. It would make an awsome addition with upward firing 20mm's for lancs and other bombers without belly turrets.
BigPlay, the Schräge Musik guns were Mk108's (30mm not 20mm), and they're pretty much useless against a target who knows you're there. They worked great if you could creep up undetected to a bomber's low-6, but keep in mind that during daylight you're going to be spotted by the tail gunner or pilot long before you get into position to fire those monsters. (especially if they're using F3) Unless of course you think you can make a near vertical approach from underneath , level off and then take the shot, in which case I

you. If I had that kind of E, I think I'd just dive on the poor guy and let all those forward-firing cannon work their magic.
