i ended up buying a check valve from a supra. i got it from a yota dealership as you cant get them from az or other parts stores looks like:
i actually popped my booster diaphragm two days ago when i spiked 30psi, got this today and im about to try it out, the part number is:
44730-2402
it runs as much as 50$ from the stealership but its a tough lil piece and its not worth it having a 20yr old internal valve blow up during a run when you might need your brakes right quick.
also my elantra booster came with NO internal check valve and on the older colt gt booster i had, the valve was sticky and didnt work quickly causing an intermittent boost leak and often no power assist after a few gears of WOT. sofor the guys who dont already have good brakes or looking to upgrade to the elantra stuff, id just add this part or something similar to your list.
also i tried a dsm pcv valve for awhille, it didnt work, just fyi.