Apexi's midpipe compliments any catback exhaust system and/or downpipe by opening up the exhaust system where it is heavily choked from Honda. The 10th gen Honda Civic Type R doesn't allow for much pressure and exhaust to flow freely out the engine with the stock engine. Putting in the Apexi midpipe on a 10th Gen Honda Civic will definitely create better power, torque, and turbo response. The pipe is made of 304 stainless steel which will hold up really well over time. Piping diameter is 70 mm, right at 2.75 inches. A flex section is built-in so vibration and flex aren't an issue as the engine moves while driving. This midpipe fits all 10th Gen Civic Type R models.