Aftermarket exhaust parts and the engine. However, the pipes do "ring" with the exhaust pulses and increase underhood noise. Headers can be ceramic coated to reduce the heat radiated in the engine compartment, and to increase the temperature of the pipes which increases the velocity of the exhaust gases. Terminology: Catalytic converters are necessary to reduce emissions but create back pressure due to the exhaust gases being forced through a catalyst, and therefore decrease high-end engine power. Many modern catalytic converters only produce 1-3 psi of back pressure, though this restriction worsens further with use. Hi-flow catalytic converters can replace the standard units
What Car? carry listings from other sources, dropping the 'Approved Used' branding. In October 2016, "What Car?" launched a new online car buying service called 'New Car Buyer Marketplace'. Built into the existing whatcar.com website, it lets readers buy discounted cars from dealers in their area who have signed up to a "What Car?" code of content. Users can add options, change trim and alter finance preferences to get a ‘live' price which dealers are committed to. "What Car?"'s 'Target Price' – a long-established recommendation of the most the magazine's mystery shoppers think someone should pay for a particular model – is