well I would first off do a compression test. Just because your motor has high miles doesn't really mean anything, it could still be in good shape. Hel;l I boosted 12psi on my stock D16z6 motor with 145k on it and it compression tested at 197 acros the board. Never ahd any problems with it. I wouldn't spray it and boost, one or the other or build it up for both.

If you need either items let me know and I can get them for you.