I did something similar to reduce lag and it helped when i stepped up to a T04E. Have a look on my website and you'll see how the piping is different to a standard 7mgte.
Another great way to reduce lag is to throw extra fuel in, about 20-25% and as the engine runs rich the exhaust gases are also very rich and heavier. These heavier gases turn the exhuast impeller alot harder and reduce spool up time.
Thats how mine is setup again to help reduce lag and get onto boost faster.