I'd be very interested in having them explain what a "transmission fluid warmer" is. Transmissions have transmission fluid coolers, but I've never heard of a "warmer". Sounds like a scam to me. Fuel system service is probably nothing more than a bottle of Techron in the gas tank. Don't let them take you for a ride saying that they'll replace the fuel filter as part of the fuel system service, most cars haven't had serviceable fuel filters for a long while, but the grifters still try to fool people into paying for the service.