IMO its comes down to what are your power goals and where to you want your power. If you want it all the answer is compounds. I have heard nothing but great things about everything Pius sends out of his shop. GQSSB being one. I really like the GTX and garretts in general for a few reasons others I am sure like different turbos for some very good reasons as well. There are certainly many great turbos out there from a number of builders etc... But IMO you first need to settle on what I started with.