hey guys,
i have the same problem with my car but with a bit of difference. it doesnt happen when changing gear and accelerating only, it happens when im going in a constant speed as well and you can see the boost gauge go nuts when that happen.
i paid over $300 to fix it or trying to fit that and still the same, checked the ecu, change the spark plugs, changed fuel filter and still the same. the thing is i told the mechanic this happen when the car is cold only so i left the car with him and when he took it to a test drive it was fine nothing happen
this problem started when i put a 95octane + booster (i use 98octane but i had to use 95 once)
i just had the car serviced today and the mechanic who had it serviced said and i quote " you got a damn good car, i never seen a legacy good as yours" >>> i dont think thats true but i guess its figure of speech
my ride is a B4 2000 manual gearbox
oh yeah, im gonna give the SUEC a go and let you know what happen