Hi this is my 1st post here so please be gentle

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I recentlly bought a 96 Impreza 2000 AWD turbo i got the car cheap cos it was a non runner, i managed to get it running with a bit of elbow grease and i have driven it over 1k miles in the past two weeks.
The car is completely standard and was very well maintained by it's 1st owner (FSH) up untill about 7k miles ago, sadley the 2nd owner didn't keep it up so i have no idea what has happened in the last 7k miles.
So now to the issue(s), i believe them to all be part of the same issue and has all the hallmarks of a vacc leak. The symptons are;
- Erratic Idle (150-600rpm).
- No power from turbo tested and is boosting to about 7-9Psi.
- The engine chokes and all power is lost and edventually dies.
- Poor Fuel eccomany (prob bout 10mpg).
- No CEL.
Other then the boost issue the issues are very sporadic and all occur at the same time i drove 200 miles the other day and it died only once and then 10 miles yesterday and it happened twice the most random part is all i need to do to fix it is leave the ignition off for a min or so. the chain of events go like this; driving along no problems at constant rpm then all of sudden there is no power and 3-4k rpm is the most i can rev to, also the engine pulls the car back like hitting a strong head wind, so i dip the clutch and roll to the side of the road just in time for the engine to die. i ask her nicley to stat mabye bribe her with offers of new parts and she fires up 1st time and drives like nothing ever happened.
I was thinking boost leak as it would explain the loss of power, and in theory the other problems, so i pressure tested the system to see if i had a leak it held pressure well. i capped it off right after the MAF, removed/plugged any pipes before the turbo and pressured it from the wastgate hose connection on the turbo. as a side effect this should have covered a vacc leak also (i think).
Shortly after i bought the car i had a vacc hose break on the highway and the car ran like a dog all the way home and this is how it feels when it starts to play up now. The idle issue has been there since day one but is not constant, i have removed cleaned and tested almost everyting found some minor issues but nothing a bit of WD-40 couldn't fix.
It smokes a little when started up cold and has a bit of fuel smell also it has a slight tapping from one of the cylinders all stops when warm, i'm thinking piston ring(s) or valve springs for this and don't think it's related to the main issue.
This is my 1st Subaru so i know very little about the issues these cars can run into at this age, my car for the last 7 years was a GTR Skyline so i know what to look out for on turbo cars but this problem has stumpped me. Any help would be appreciated, if you need anymore info i'll supply what i can.