Splitting the wastegate farther is fine if you are will to give up the ease of working on the car and the ability to put stock cats back in for smog. What is not a good idea is keeping the main turbine tube small for that long. By keeping the main tube small that far back you are defeating anything the 3 inch pipe has to offer. 3 inch works if it has a proper down pipe that expands quickly and offers more room for the hot gases to release and keep from building backpressure. Interesting that they stepped up the wastegate tube a couple times :-) The only reason you would need to make the wastegate tube larger is if you had boost creep with the 1.5" wastegate tube and we do not. You would always want as much exhaust gas to go through the turbine tube side as possible to drive the turbine. The design of making the wastegate tube step up has no logic and shows that the designer lacks the understanding of how a turbo works. I am sure you will see a gain in spool up by getting rid of your gutted cats.
