“For when one regards their elegance and dignity, it is impossible that his lust will not be awakened to desire these things. And even if he will not permit his evil inclination to conquer him, he will, in any event, not escape the battle and its dangers.”
Seems to me this alone is a raya why people who buy luxry Gucci shoes and luxry cars should be rebuked. They will undoubtedly cause others to either spend more hours at work to attain such vanities or engender within them and their wives and children envy. Mesilas Yesharim says it is IMPOSSIBLE for it not to. So if not in order to give more tzedaka, this alone is of sufficient reason.