summit racing has single port manifold with a cat where the pipes join. I dont know if it is a performance part but should do fine.
http://store.summitracing.com/partd...4294923429+4294907499+400320+115&autoview=sku
http://store.summitracing.com/partd...4294923429+4294907499+400320+115&autoview=sku