As I understand it, the "vac" lines to the oil injectors aren't really vac but rather provide air to the injector to help both atomize the oil as well as prevent extra oil being sucked up by the vacume from the intake stroke of the rotor. You can remove them but then the oil injectors will suck raw air into the chamber rather than filtered. Theoretically, it would be equivolent to a vac leak, but I'm not sure how significant.
-b