I recently bought a 1990 GXL that someone had replaced the exhaust on. It also came with many exhaust parts. I know there is a 3" downpipe for a turbo but can I use the other part for my non turbo 13B? Can we use a header or a downpipe? Can we just use a header and no downpipe? What are the options?

 

A header is for an NA. A downpipe is for a turbo. The exception is Racingbeat's NA downpipe, which bolts onto the stock exhaust manifold.