Honda S2000 High Flow Cat Upgrade: What to Know
By REMARK Exhaust | Published: 2026-10-24
Category: Product Reviews
Considering a high flow catalytic converter for your S2000? This guide covers performance benefits, fitment, and key decision rules to help you upgrade wisely.
Quick answer
A high flow catalytic converter is a worthwhile upgrade for your Honda S2000 if you want reduced back pressure and increased exhaust flow without sacrificing EPA compliance.
What a high flow cat does for your S2000
The factory catalytic converter on the Honda S2000 is designed for emissions compliance and quiet operation, but it also creates significant back pressure that restricts exhaust flow. Swapping to a high flow unit—like the REMARK High Flow Catalytic Converter—uses a metal substrate with a 400 cell count to reduce that restriction while still filtering exhaust gases.
Trade-offs to consider
A high flow cat is not an OEM replacement part. It is built for enthusiasts who want more flow and a sportier exhaust note. You may notice a slightly louder tone at highway speeds, and the converter will not reduce emissions as thoroughly as the factory unit—though it remains EPA compliant. If your primary goal is emissions compliance for a strict inspection, an OEM-style converter is the safer choice.
Decision rules for your S2000 cat upgrade
- Performance goal: If your aim is to reduce back pressure and increase exhaust flow for a naturally aspirated or boosted S2000, a high flow cat is a direct upgrade.
- Sound preference: Expect a deeper, more aggressive exhaust note compared to stock. If you prefer a quiet cabin, consider keeping the factory cat or pairing with a resonated exhaust.
- Emissions compliance: The REMARK High Flow Cat is EPA compliant, but it is not a direct replacement for every state inspection. Check local regulations before purchasing. Verify your state's emissions testing requirements before ordering.
Product facts
- High Flow Catalytic Converter - Honda S2000: This metal substrate catalytic converter has undergone Federal testing and is EPA compliant. You get the performance benefit of a high flow design without worrying about legal issues in states that follow federal emissions standards.
High Flow Catalytic Converter - Honda S2000
Who should upgrade?
Best for
- S2000 owners who track or autocross and want maximum exhaust flow
- Enthusiasts planning a full exhaust system upgrade (header, test pipe, cat-back)
Not for
- Drivers who need strict OEM-level emissions compliance for a visual inspection
- Anyone wanting to keep the stock exhaust note and volume
