A selection of the most common questions that we are frequently asked, from fitting the system, performance information and cleaning tips.


Power Gains


Q. What sort of power gain can I expect to get?
A. Each car has it’s own characteristics, and the power gain can vary greatly between them. 8-10% is about the most accurate general figure to cover all variations.

Sound Information


Q. I want a sporty sound, but not one that is so loud that it wakes the neighbours or annoy me on a long journey. What sort of sound do your systems produce?
A. As our slogan states, ‘Performance to blow your mind, not your ears!’ our engineers’ mission is to find the perfect balance between maximum performance increase while maintaining a responsible noise level. We DO NOT produce boy-racer style exhaust systems that can be heard from miles away. Our systems are designed to appeal to enthusiasts of all levels and the main way of controlling this is by offering resonated and non-resonated versions of most of our systems – see below for further information about the differences between resonated and non-resonated).
Q. What is a resonator and what’s the difference between a resonated and non-resonated exhaust system?
A. A resonator is a chamber in the exhaust system that contains a specific volume of air which is designed to cancel out certain frequencies of sound (made by the engine) – making the exhaust noise quieter.Therefore, a non-resonated exhaust system will give you extra performance and a louder exhaust note and the resonated system will give you extra performance without increasing the exhaust noise much.
Q. What alternative do I have to a de-cat?
A. A Hi-Flow cat will increase flow by as much as 30% over the original manufacturers unit.



Q. Can I buy parts individually (e.g. can I buy just the cat, or just the downpipes or backbox)?
A. Hi-Flow cats are available as stand-alone purchases, otherwise units are sold as either cat back or rear box only, because Milltek are genuine performance systems you can’t mix and match.



Q. Will I need to modify my vehicle in order to fit Milltek products?
A. No. Our products are direct replacements for the original systems and come with everything needed to fit them. There are some vehicles that may require different rear valances to be fitted to allow tailpipes to exit the rear bumper (e.g. VW Golf Mk4) but this will be made clear to you.

Aftersales Care


Q. Is my exhaust system covered by a guarantee or warranty?
A. As long as you are the original purchaser, cat-back exhaust systems are covered by a lifetime anti-corrosion and manufacturing defect warranty and hi-flow sports catalysts and downpipes are covered by a 2 year or 80,000km warranty. We do not cover against any modifications made to our product after it has left our factory and also not for unusual use of the parts – for example, the use of Nitrous Oxide (NOS), damage caused by going over a speed bump too fast etc. Our warranties are offered on the understanding that the cars power maybe increased by up to 33% from it’s original specification. Modifications made to increase the power beyond this will render the warranty void.We pride ourselves on our after-sales support and customer service and will look into each case on an individual basis.All warranty cases should be dealt with by the Milltek appointed distributor from whom you purchased the system. However, if you are dissatisfied with the service of your distributor in response to your claim, you can contact us directly by emailing us at info@nzperformancetuning.co.nz.Please note: Milltek Sport hi-flow sports catalysts are manufactured from the highest quality materials and built with maximum performance and longevity in mind. However, they are designed to work specifically in conjunction with other Milltek Sport products and should not be used on their own (with the OEM exhaust system) or with other manufacturers exhaust systems. If the Milltek catalysts are fitted with non-Milltek exhaust systems, we are unable to provide any guarantee regarding noise quality, fit, performance or warranty against their operation.

Cleaning Tips


Q. How do I clean my stainless steel tailpipes without scratching or damaging them?
A. It is important to note that if you don’t clean your tailpipes regularly (and we know that some of you don’t 🙂 ), they will suffer from discolouration and become harder to clean. Because of the high-quality stainless steel, you will always be able to get them back to looking brand new (without any degradation in the materials), but the longer you’ve left it without cleaning them, the harder it will be!Our tailpipes are made from the highest quality polished stainless steel, we have found that the best way to clean them is to use a Silver Polish. The actual specific product we use is called Silvo Silver Polish with Wadding. It’s important to get the one with the wadding inside as it’s really good at getting it clean. Clean the bulk of the soot off the surface with an old rag first and then use the polish/wadding to get your tailpipe(s) sparkling again.