Other than that, the EGR is just a tool that does exactly what it says it does. Exhaust Gas Recurculator. It takes small amounts of exhaust gas (carbon dioxide) and injects it into the intake manifold. The exhaust gas injected into the intake manifold mixes with regular air, so when the mixture of air and carbon dioxide is put into the cyclinder to burn, the combustion is not as great because it is not 100% air in the chamber. In a way, you can say the carbon dioxide redirected into the intake manifold is designed to keep the potential of your motor down.
If tuned properly then you will have no problems. And don't forget that you won't have carbon build up anymore.
