Dinan offered a larger intake tube to match the 4" MAF which connected to the Dinan throttle body that also was 4". That made it 4" from the air filter to the intake. Anything that is not 4" will be a reduction from max HP and TQ available when all the other mods are in place. There was software for each level of Dinan mods. They also offered a Dinan exhaust. If you have all the engine mods and the exhaust and stage 4 software the result is 369HP at 5700 5700RPM and 382TQ at 4500RPM. The transmission software is great, good purchase. The exhaust alone was worth 8HP and 6TQ at 6500RPM. Some of the pieces are still offered by Dinan at dinancars.com.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas