Expensive Gift From Inlaws
The car is given to you and your wife by her parents as a gift. First of all, from the seerah of prophet Muhammad SAW we know that he accepted gifts and encouraged us to exchange gifts as well. Secondly, please keep in mind that they’re your wife’s parents. If they want to give her (or you or your children) anything, you should respect that. If you want to lead a humble life, that’s very understandable. However in that case, you could have communicated your preference for a moderate car instead of a luxury car when they first informed you about it. Besides outright rejecting a gift is not very humble in my opinion. Lastly, elitism, egalitarianism, and populism are political philosophies. You should consider if your political preferences are more important to you than your marriage. As you grow older, your world view (and most probably your political preferences) are bound to change. However, if you allow friction in your married life from the get go, you might have to pay a price for it for the rest of your life. As a final suggestion, I would request you to rise above ego and emotions, think empathetically, and then make your decision. God bless!