It would be unbalancing if everyone flew it to its strengths, in numbers like the chog was used before it was perked. The two are different animals, but that's the yardstick - whether it upsets the balance. The 190A5 couldn't nearly have the same weight on gameplay's balance because it's not good enough. The XVI's effectively just not good enough in the hands of most of the players that use it. Hence the spit16 could but doesn't unbalance gameplay. I don't think it's worth more than 2-3 perks anyway.