I believe we've been over this topic before, and someone cited that the german stuka G1 and G2 pilots hated attacking soviet M4's (M4A2's, the main export variant, given to the USSR) becuase they would often take pot shots at them with their main guns. Sorry, I don't have the source, internet is being slow, hence the search is being slow

.
As to the argument that there is no recorded incident of an aircraft being shot down by a tank, well all I have to say is this, quoted from the constition: "Burden of proof rests with the accuser, not the accused". Show me proof that it DIDN'T happen, and I'll shut up (by the way, lack of evedince that it did happen isn't evidence that it didn't. All that is is a testement to the chaos of WWII)
And now that I've been rational, I can give forth with my oppinion to the OP: Nut up or shut up, if your going to make low angle attacks. Low angle = low life expectancy.
High angles are more effective with strafer aircraft too, by the way (top armor of the panzer is only about 15mm IIRC).