Hi guys, i'm back!

First of all, I need to say my Turbo is 305RWHP and 350RWTorque. Maybe usefull for the next question..
I ask myself since I read different posts on which oil is better for a 944 Turbo..
Well.. I kept the 2 answers that was the most recurrent.
Some of people are using 15w50 or 0w40, all those 2 from Mobil 1.
Personally I'm using 15w50 but the oil level is dropping not very fast but.. if I put the "pedal to metal" for some short acceleration on the highway.. the level drop more than normal I GUESS. The stick pass from full to 3/4 in about 3 weeks. I want to specify that I use it only for street right now and I dont always push the car.
What you guys think about the 0w40 ? Because I will probably try it. I need to change my oil this weekend then I will wait for some answers before go buy oil.
What are you 944 Turbo oil consumption and which oil you use!?
Thanks a lot guys!