AFAIK, if the engine will retune itself.? Same as if you fit a free flow air filter.? The air flow meter works out flow rate and density of the air, the injection system will then refer to the map to work out how much fuel is required for the current load on the engine, mix the two together and fire it into the cylinders.? The lambda sensor works out how well the mixture is burnt and backs off the fuelling slightly if required to cut down on emmisions and increase economy.
This is not gospel, but my take on how it works.
You could have the chip reprogrammed, but thats a different thing all together.
Where did you get the exhaust from BTW, I'm interested in going down this route myself.? Theres a place near where I live (outside Blackpool) that makes SS exhausts to order.
