Cooling intake air is vital to keeping any TDI running strong. High intake air temperatures will significantly reduce engine torque and fuel efficiency and cause more smoking. As intake air heats up the TDI ECU will also cut back fueling. This TDI specific, upgraded side mount intercooler has a larger surface area and more efficient fin design. This intercooler has a MAP sensor port. If your TDI from 1998 or 1999 has a MAP sensor port on the upper pipe you will need a MAP sensor plug to close this extra hole. This SMIC will not work with BEW models with OEM piping. BEW cars require swapping to ALH intercooler hoses to fit. This is the same one the other guys sell for over $300 Volkswagen Golf TDI MkIV (A4 chassis) w/ ALH Engine (1999-2003) Jetta TDI MkIV (A4 chassis) w/ ALH Engine (1999-2003) Jetta Wagon TDI (A4 chassis) w/ ALH Engine (2002-2003) Warranty All parts have a 30 day return warranty. Part must be received back in the same condition it was sold in. All returns subject to a 20% restocking fee. Shipping charges are non-refundable.