could be or turbo seals, etc etc.
basicly oil is getting somewhere it shouldn't be, given the mileage i wouldn't be surprised if it needed an engine refresh, my type r's engine was pretty much worn out at 104k and while prob been driven harder than yours milage still does the same thing.
all the biggies are like it. Tis a sad reflection fo the current gaming industry. i noticed cjs have reduced it down to £51 for the pair now, im actualy getting tempted.
http://www.cjs-cdkeys.com/products/Fallout-4-CD-Key-For-Steam.html
First bit of advice as far as subaru tuning. Stay away from ebay. Unless its a known branded part, such as miltek etc then just leave well alone.
Allot of ebay parts will loose power, if they work at all.