By sheer coincidence, WSJ has a review of the X4 and thumbs down the “expensive upgrades”
=====
"2019 BMW X4: Why You Should Skip the Upgrades
Is a bigger, badder engine actually worth the extra price? What about driver’s assist and damper control? Dan Neil drives two versions of BMW’s latest X4 and considers the real costs of upselling
But the biggest upsell of all is also the one least likely to bring happiness: more power. The X4 is also available with BMW’s turbocharged 3.0-liter, 355-hp in-line six cylinder. That one they call the xDrive M40i M Performance trim level, and it starts more or less where the fully equipped xDrive 30i leaves off ($60,450 base MSRP).
I drove both versions at a June press event at BMW’s factory in Spartanburg, in the Bavarian region of South Carolina, and came away convinced that, were it my money, I would absolutely choose the smaller, more fuel-efficient engine (29 mpg on the highway, according to the feds). If you listen closely you can hear the hearts of BMW sales managers breaking.