RE: Dual fuel system

I have received 2 different quotes with Trane equipment. They are the same except for the furnace. One of them has TUX1B080A9421A. The other quote has TUC1B080A9421A. I was told they are "basically the same, but the TUC1 is $550 cheaper". So what is the difference other than price? Is the TUX1B significantly better?

Thanks.