Originally Posted by amoosenamedhank
The CFM rating is not dictated by the turbo, but instead by the displacement of the engine and the rpms you're at. That is a constant unless you change something in the system.
This is not accurately stated. The CFM most certainly is dictated by the turbo, by both the turbine side and the compressor side.
A small turbine housing will restrict flow, and a small compressor will restrict flow.
There is too much over-simplification in your explanation and the original poster needs to do far more reading on their own rather than expect to get all the answers here by non-professionals, including myself.
Go to the Garrett website and read everything before accepting anything you read here as fact.
EDIT: I'll add that I recommend not buying a single piece of your turbo kit until you can read, understand, and plot points on a compressor map relative to your power goals.
If you don't want to do any of this, then just buy a pre-made kit from a company that has done all the research already.