5Zigen Dowpipes R35 GTR 09+

Price: $1,199.99

These are made of lightweight stainless steel and have provisions for both stock oxygen sensors. They remove the stock primary catalytic converters, thus allowing MUCH better exhaust flow and sound. These are not emission legal and are for off-road use only. Most manufacturers use 75mm piping, but 5Zigen has stepped it up a bit with their 80mm piping.