Hello, STP engine air and cabin air filters are a price point and quality (perceived) I prefer. The Mann filters I get do seem a little heavier than a STP or Fram therefore possibly better. Charcoal impregnated cabin filters at $39-$45 aren't what I want to buy. I believe they can't last more than a few hours because they're exposed to the air. STP offers me a disposable, rugged paper element. I've come to prefer them. Also, the real cheap, vacuum formed, wavy white fiber filters-like the TYC brand-are so cheap they should be $2-$3 but they're not. The parts warehouse I go to had those at $7. I went for my second one and the price was $17. Sorry to mix engine and cabin in my post but you get the idea. Kira