Here is the pair of HVH-Brodix manifolds we tested. As you can see, there's quite a bit of difference in the configuration of the manifolds. The dual-plane is likely very street-car friendly and will easily fit under most stock hoods. Meanwhile, the SP1 is a tall, race car configuration, geared more to a more radical combination. What's with the spacers? We also flogged various HVH Super Sucker and Street Sweeper spacer combinations on a variety of manifold types.