Interesting. Just got an oil change this weekend on the STi and it's only her third, but I have been with Valvoline SynPower since the first. I keep my receipts so good to know.
I used Valvoline SynPower in my previous WRX and now in my STi, as well as my VX, but I switched my VX over to Royal Purple with the last few. Very smooth and I would recommend it for anyone hard on an engine.
http://valvoline.com/products/consum...ic-motor-oil/5