These sit in different parts of the exhaust and solve different problems: a catback system replaces everything from the catalytic converter to the tailpipes, while a decat pipe is a single section that removes the catalytic converter entirely. They're often cross-shopped by people who really just want more sound and flow for less money.
| Spec | Catback Exhaust System | 2.5" Exhaust Decat Pipe |
|---|---|---|
| What it replaces | The full system from the catalytic converter back: mid-pipe, silencer(s), and tailpipes | Just the section containing the catalytic converter |
| Catalytic converter | Stays in place, the factory or OEM-style cat is retained | Removed entirely and replaced with a straight-through pipe |
| Construction | T304 stainless steel, free-flowing system with polished tailpipes | Stainless steel straight pipe, no cat, no silencing |
| Road use | Designed as a road system, check current UK MOT emissions rules for your car's age | Removing the cat can affect emissions and MOT compliance, check current UK MOT rules before fitting for road use, this is generally treated as a track-focused part |
| Catalogue price | From £489.99 (Japspeed UK) | From £99.99 (Gravity Performance) |
A catback system is the more complete upgrade: new mid-pipe, silencer, and tailpipes, while keeping the catalytic converter in place. It's the pricier option, but it's built as a full road system rather than a single component swap.
A decat pipe is a fraction of the price and does increase flow, but it removes the catalytic converter entirely, which is an emissions component. Whether that's acceptable for road use depends on your car's age and current UK MOT emissions testing rules, so it's worth checking the official guidance before fitting one if the car needs to stay road-legal. Many owners treat a decat as a track-day-only part for this reason.
It depends on your car's age and how UK MOT emissions testing applies to it. Removing the catalytic converter is an emissions-relevant modification, so it's worth checking the current DVSA MOT guidance for your specific car before fitting one if it needs to stay road-legal. Many owners run a decat as a track-only part and keep a catted system for road use.
No. A catback system starts from the catalytic converter backwards, so the cat itself is retained. It's the mid-pipe, silencer, and tailpipes that get replaced, not the emissions component.
Prices and stock shown above are pulled live from our parts catalogue and may have changed since this page was last built. The Car Scene may earn a commission on purchases made through retailer links, at no extra cost to you.
