Improving exhaust flow is pretty much a no-brainer, especially for turbo vehicles, which require as little restriction as possible to be most effective. Achieving lower under-hood temperatures due to free-flowing design, more horsepower, and increased turbo spool-up can all be had with an upgraded Audi S4 turbo manifold, regardless of construction material. If you're building a high-horsepower turbo monster, an upgraded Audi S4 turbo manifold should be one of the first things on your shopping list.

A good Audi S4 turbo manifold is almost as important as an upgraded turbo when it comes to performance, but there are some considerations to make when making a choice between cast iron turbo manifolds and tubular steel manifolds. If space is a concern (tight engine bays or retaining air conditioning or power steering), a cast Audi S4 turbo manifold will usually be more compact in design and generally stronger, although it will be heavier than a tubular unit. However, for all-out power gains, most tuners tend to go with a tubular steel Audi S4 turbo manifold due to their better flow characteristics and lighter weight.

Q: What is a turbo manifold? Why buy one?
A: For most cars, if you have a turbo installed, it means you do not have an exhaust manifold that is connected to your engine head, but instead of a turbo manifold that is connected to the turbo. The turbo manifold is the front end of the exhaust system on turbo-charged vehicles. Buying an aftermarket turbo manifold can give you more horsepower since they are designed to let more airflow through and therefore create more power.