Q. What does 'cell count / CPSI' mean?
A. CPSI = cells per square inch in the honeycomb substrate. Lower CPSI generally flows more freely; higher CPSI usually provides more surface area for emissions conversion.

Q. Which should I choose: 50, 100 or 200 cell?
A. As a rule of thumb: 50 cell = maximum flow, 100 cell = balanced, 200 cell = common 'streetable' compromise for flow vs. emissions/odor control (varies by vehicle/setup).

Q. Do you stock the right size for my exhaust?
A. Our range includes common diameters like 2" / 2.25" / 2.5" / 3" / 3.5" / 4" (check each product title/specs to match your pipe size).

Q. Do any options include an O2 sensor port?
A. Yes - some models list 'O2 Sensor Provision Included' in the description (confirm on the product page before ordering). 

Q. Will a high-flow cat stop a check engine light?
A. Not always. Some vehicles are sensitive to catalyst efficiency readings. If you're chasing a CEL fix, check our 'Check Light Elim' range.

Q. Are these petrol or diesel?
A. We have a range of Hi-Flow Cats to suit both Petrol and Diesel engine types.

Q. Is a high-flow cat legal for road use?
A. Rules vary by jurisdiction and emissions requirements.