I think you need to buy considering the circumstances. It would be ideal if you bought a couple 99's with value who'd be around next year. That way, if you chose to sell off in the off season and into next year, they'd bring some decent value in trade. Rangers have four such 99's but they'll be looking for at least one young body in return. If you targeting Yantsis and Garreffa, I'd assume Woolley plus picks plus conditionals would have to come the other way.
Swapping out Poirier for a stud OA makes sense too. And could be done cheaper than trying to acquire a 99 stud that may cost you a Chayka. Could Eliot be had for just picks?
Truth be told though, not having immediate help for a playoff run come back in either the Primeau or Bertuzzi deals hurts.