FWIW the billet spacer has not been an issue for leaks for a long long time . when the remote ipr was added the original design work fairly well but not as anticipated , and a few of them leaked .but ever since the redesign has not been an issue ...as long as you don't strip the front timing cover you should have no more leaks issues then you would normally have on a single pump ... so in short there is no leak issues except for the factory problems . Meaning the service port etc....and ,you have all the reliability of the factory bosch pumps.