ETS Stainless Steel Race Series Exhaust - Nissan GTR 2009+The ETS GT R 4. 0" Stainless Steel Exhaust System is one of the largest and highest flowing exhaust systems on the market! The key to making horsepower in a turbocharger vehicle is by eliminating back pressure and we do this by using a full 4. 0" exhaust system without any compromises. One of the many key features of our exhaust system is a true 4. 0" merge collector. This is important because around the 1200whp range most exhaust systems will start