I am using the ES 26G pipe with my 160FX. I had it left over from a previous project. One of the larger diameter pipes might be a bit quieter. Exhaust duration was increased from 142 to 154 degrees. 8200+ with an APC 18.1x10. Good power for my overweight Focus.

ES pipes made in the last several years use the same resin as the ES gasoline engine pipes which see higher temps than glow engines.