This is pretty straight forward, give the exotic khvostov the lige exotic perk so it doesn't take up your exotic slot. If there is any weapon that deserves this it's the khvostov it was made to be purely nostalgic and therefore it's a shame I can't use it becuse there are so many better exotic options out there. (gally anyone) Giving us the ability to pair the khvostov with another exotic isn't gamebreaking or OP either since the khostov really isn't that strong and the exotic properties of this weapon are its nostalgia and it's very customisable. This won't result in everyone running a khostov either since many legendaries out there are stronger than the khvostov and the only real reason to use it is for fun. So in conclusion give the khvostov the life exotic as an intrinsic perk so it can be used at the same time as another exotic.