The n1 muffler series has evolved once again! the n1 exti (expert titanium) offers all the performance and quality of our race proven n1 exhaust systems plus the incorporation of an ultra light weight titanium muffler section. for years, the n1 titan has only been available to our customers in japan; at a'pex usa we are very pleased to be able to offer this muffler to the us tuning market under the n1 exti name.