excellent, what are the symptoms?
poor idle, lumpy, easy to stall, hesitations when going on throttle are signs of unmetered air getting in, ie leak after maf but before throttle
best place to look is the pcv valve, fastest way to check is disconnect pcv from turbo intake pipe, clamp the pcv hose that connects to the inlet manifold, wipe pcv clean and then blow into it. it should be air tight
the pcv hose on the intake manifold is mega common to be burst.
as for the vacuum system, it is very easy to simplify. you have two vac nipples and you want them to run the dv, fuel pressure reg and n112 valve. you need new silicon vac hose and a t peice and youll never have to worry about the vac system again