True, but the mk108 has balistics that are just TERRIBLE. Anything with Hispanos, Mg151's or .50's will shread your cocpit before your 108's get on target (trigger for them is the same as for the 20mm's)
To be honest I have an easier time landing Mk108 30mm rounds in the 190A8 than in the 152, the 109s K4, G14, the old G6, and the 163. For some reason the ballistics "seem" easier even if only slightly. Placebo effect, no doubt, but these weapons multiply your effective killing power for as long as they last. They are more than worth the weight.
Lusche is right that you do not have to take 30mms (or even outboard guns at all). I've flown a A8 with 2-gun package before and mixed it up. I'm not saying it was "nimble" exactly, but I've done it. I'd suggest just up the A5 if that's what you want to do, or a C205. The entire point of putting up with the sluggish weight and horrible handling of the A8 is the extra firepower. That, alone, is why it is so much more lethal a killing machine than the A5.