Footwell module, yeah unfortunately. Mines been replaced once under the extended warranty, $800 installed at the dealer in 2015.

Emissions control systems, yep. That's the worst part of the entire drivetrain. Get the engine to operating temperature often and don't let it suffer short, 'down the road for snacks' trips.

Turbo is another 200k+ (really plus) mile item. Use the "best" oil with the lowest SAPS, highest NOACK volatility, HTHS and flashpoints, let the turbo cool down for a bit before shutdown and you will maximize that service life.

The vacuum system hoses and other hoses (boost piping) will get old and probably age out. The canister can crack, too.

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8/2011 X5 xDrive35d Sport, Black Sapphire Metallic, Black Nevada Leather, Fine Burr Walnut Trim
2/2001 M5, Jet Black, Exclusive Complete Black Walk Nappa Point Heritage Leather, Black Cubic Trim