Akrapovic Slip On Line (Titanium) for BMW F40 M135iSO Slip OnBeautifully crafted from high grade titanium, this lightweight exhaust system is finished with eye catching carbon fibre tailpipes and is a full on sensory delight. The exhaust valve with its housing cast in the in house foundry gives the exhaust a rich sound with an emphasis on high frequencies, especially when shifting through the gears, all allied to a deep tone that enhances the cars engine without any discomfort or drone for the