Bummer. It might be fine to run as is. It's no fun to pull them once their in. If heat isn't an issue on the contact spot on the sensor, run it. Maybe a thin piece of aluminum wedged in between to act as a heat sink/shield. You can also maybe back the tension off the header header studs to maybe get a little wiggle room. Just shooting some ideas.

Did you weld up some cats off the collectors? Send a picture if you can.

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2005 X5 3.0, 6MT, Alpine White on Truffle Brown, Sport, Preim, and Cold Weather, Alpina Stainless Headers, AFe Intake, UUC SSK, OEM 87's, 3.64 Differential Swap,Performance Modified Euro 2 Tune, UUC LTW Flywheel and HD clutch, Bilstein B12 Suspension kit
Future mods ZHP/Schrick Cam Shaft upgrade, Operation code name:Doppelschrauben-Kompressor

Wife's Ride: 2011 e70 X5 351 M///Sport.

Also in the fold: 2004 X3 3.0, 6MT, Black Sapphire on Terracotta, port, Premium, Cold Weather.