I am running Royal Purple 10w-40 in my 03' WRX and it has 91k on it. I have a catless DP and P&P TD-04. I am burning about a quart of oil every 200 miles and smoke pours out of the tailpipe, it's blue and smells like oil. I am very concerned about this and was planning on putting in some type of 5w-40 soon (hopefully Motul). I just did a turbo swap at 89k and I used 20w-50 conventional to break it in. Could this cause me to burn so much oil or is there something mucu, much worse going on? The car runs great and still pulls hard and other than the smoke (intermittently occurs) it runs like it always has. Am I looking at a very serious problem or could it be because I'm using 10w-40 Royal Purple?