FYI- Blown MAFs due to CAI plagued mainly the Impreza world not Legacies. RSs came with film MAFS that were very sensative to Manifold resonation. After installing the CAI a lean out condition would occur because of the resonation at higher RPMs. Eventually it would break the film. Legacies came with Hot Wire Mafs which are !!!!WAAYYY!! more durable.
My Weapon R has been installed since early 2000. I haven't had any problems. I would suggest getting a very beefy bracket to mount the intake and prevent too much vibration.