alright bud, did the one way valve trick today, haven't had chance to road test the car but first observation is a crazy amount of vacuum in the valve covers, when you remove the filler cap it sounds like a friggen dyson... is that normal?

Not on the 200sx, it's a (relatively) well-known cure for weeping seals on idle (Google "One Way Valve Trick"). Without having the car in front of me, it's difficult to say.

 

The valves are between the front rocker outlet & the turbo intake piping, with the valves positioned to allow the engine to breath into the piping as stock, but not allow any air to flow the opposite direction? I can't see how it's resulted in what you're describing. I have mine vented to atmosphere, and if I put my fingers over the end of the pipes, it doesn't create a vacuum in the valve covers.

Yeah I did some research on sxoc aswel as doing a fair bit of reading about breather systems generally, I've got the valve facing so that on idle its shut, creating vacuum and when on throttle the sump pressure opens to relieve the positive pressure into the elephant trunk. My understanding of it creates larger vacuum in the crankcase so oil is not allowed to pressure against the seals and weap. I expected some vacuum pressure nut not quite that much lol. My only assumption is my seal is in fairly good nick(being new) normally gasses passes the seal and negates vacuum business.