I agree with rharv's answer.

In my opinion, will the audiophile version (which I have) be "much" better sounding? No. It is better sounding, but not by a great deal. As of version 2011, again only in my opinion, there is even less of a difference than there used to be.

If you are listening in a quiet environment like a studio with pro-level equipment, and you have good ears, then you can hear the difference (especially on certain instruments, such as solo acoustic guitar, and certain parts of a drum kit). Anything less than those conditions and it is more hard to tell. The one exception to that is to remember that noise is additive in a mix, so when mixing many RealTracks into a finished song, it is more likely you can tell a difference more easily.

About making the final mix into an MP3, in my opinion the bit rate you choose to encode the MP3 will make more of a difference than the audiophile versus regular RealTracks, but every mix is different.

BIAB 2024 Win Audiophile. Software: Studio One 6.5 Pro, Swam horns, Acoustica-7, Notion 6; Win 11 Home. Hardware: Intel i9, 32 Gb; Roland Integra-7, Presonus Studio 192, Presonus Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors