I understand the point you're making -- the value of expensive things in signaling to someone you don't know. I can't see the point in marrying someone if I couldn't trust them with my bank account.

Edit: I'm realizing that this is entirely from my perspective. How does a woman without earning potential display her husband's wealth to her family and friends? She asks him to buy her an ornament to prove how much he values her. This puts the man above the woman, inequalizing them.

Is there any custom where a bride and groom exchange gifts of equal value?

No matter how nice a car is, the large-scale social consequences of flashing a status symbol should be considered before purchasing a brand associated with that, especially for a daily driver.

Last week I was in a sales training course where the trainer explained 'leitmotifs' of buyers, one being 'status', his example being 'a guy driving a Porsche and wearing a Rolex'. Of course there was one guy there with a Porsche and a Rolex who then found it necessary to defend his choices as being objective, rational, etc. (He didn't need to, but I guess it's hard not feeling being put on the spot in a situation like that). Still it was funny seeing him squirm while being hit over the head with all sorts of variations of your argument. (not that I disapprove of status symbols or some such thing, I'd buy them if I could afford them I guess :) )

Not sure what you mean here - are you saying 'show everybody the receipt'? That's not signalling, signalling includes 'being socially acceptable', which talking about how money you have or walking around showing your ATM receipts certainly isn't.