Tomei Expreme Ti Titanium Catback Exhaust System - Subaru WRX/STi 2002-2007Tomei starts with the very best in raw materials and takes it to the next level. This exhaust is about one thing and one thing only; performance. They have started by stripping the weight down to what feels like nothing compared to the stock exhaust. They did this by using titanium over steel and making the exhaust as straight as possible. Less bends means less materials used. They even went so far as to think about the extra weight regular style