I have only had them in my car for 4 days so, I can't really say if I like them or not. I have always used NGK's in 3 of my previous Audi's and absolutely loved them. The PO had the plugs done about a year ago but the shop had installed resistors. I looked on the service record from that time and it says they put in H9DC's but, it seems that they placed an order for them but, received the resistor type as the H9DC's have been superseded and just threw them in there anyway. And yes, NGK's heat range is the opposite of Bosch's, the lower the number the hotter the plug (on NGK).