Exhaust performance............

How much more horsepower does each of the following exhaust systems give for the Tacoma 2.4 4cyl?

1. Jardine exhaust system
2. Gibson exhaust system
3. TRD/Borla exhaust system

Anyone have an idea?

Anyone with these exhaust systems, have you dynoed or used g-tech pro to find out their performance?

Good topic, someone give some feedback