DAC upgrade on a reciever

I am new to this forum, so if I do something out of line, please inform me gently and I will promptly change it.

I have a (relatively) new digital reciever (Harman Kardon AVR-65) on which I want to upgrade the DAC, since it only handles 32, 44.1, and 48 kHz signals on the digital optical and coaxial inputs. I'm not sure the word length that is accepted, but I assume it can choose between 16-bit and 24-bit for CD and DVD.

I want to purchase a DVD player that supports not only the 96kHz/24 bit DVD audio sampling rate, but also the 192kHz/ 24 bit DVD audio rate, but as I specified above, my recviever's decoder will only handle rates up to 48 kHz. Is it even feasible for me to open up my reciever and replace the chip with one that is able to handle these higher sampling rates? If so, what would be my first set of steps? What are the pitfalls? I'm moderately competent in the area of chip replacement, ect. since I worked on medical electronics for quite a while, so most changes to the existing DAC should be possible for me.

After reading most of the posts here, I didn't see one that talked about upgrading the DAC on a digital reciever, but instead talked about upgrading the DAC on a CD player. That being said, any and all info about reciever DACs is greatly appreciated.

BTW: All things being equal, I can buy a new reciever with the desired DAC for less than I can build an entire external DAC, and, since cost is a HUGE factor for me, I am looking for the most cost-effective upgrade possible, so please don't advise me to go buy a $300 kit for an external DAC.