Looking to improve CD playback

Ok, currently I am using a Arcam DV137 DVD player as a transport into a Bryston BDA-1 DAC via SPDIF coax.

I am considering the purchase of the Mirror Audio Tubador III DAC and the NuPrime CDT-8 dedicated CD transport. I have been keeping up with the threads regarding the Tubador DAC.

The Tubador can be purchased with I2S output via HDMI I believe this is an additional $400 cost to a $1500 DAC. The CDT-8 has I2S output via HDMI. I believe the general consensus is that I2S is the best interlink between digital components however have no personal experience using I2S. I know there are different connection types other than HDMI for I2S however lack knowledge about the benefits of any of the different types. I am looking for feedback on this DAC/Transport combination regarding benefits of the I2S connection provided.  

Obviously, I have options regarding timing of purchases. I could buy a the transport 1st and use SPDIF into my BDA-1 to explore the benefits of the CD only transport over my DVD player. I could purchase the Tubador without I2S at a later date. The Tubador could be updated with I2S at a later date if desired.  There are other transports available.

Any thoughts on this rather open ended question?