If the speaker is not flaking and impairing the sound quality and you "really" like the look of this engine but hate the passenger station dialogue (voices and content), with access to a DCS TIU/remote you can switch the engine's personality (sound) file. As others noted there does not appear to be another 5v Sante Fe F unit passenger soundfile available. However, there is another EMD prime mover with MTH's Railking E3 (30-2227-1 http://www.mthtrains.com/content/30-2227-1) passenger 5v file that might be more to your liking: http://www.mthtrains.com/sites...sf_020128b_final.mth
The Railking E8 (30-2271-1) is also available in 5v.
http://www.mthtrains.com/content/30-2271-1
file:
http://www.mthtrains.com/sites...___sf_020513cfin.mth
If your dealer is nearby and has access to a DCS TIU/remote he might be the one to ask to do the file change in an effort to keep the sale and show customer support. The original sound/personality file can also be switched back to the engine if you do not like the E3's soundset.
There is also the option of putting in the 5v ATSF passenger files of a non-EMD engine such as:
FairbanksMorse's C-Liner
http://www.mthtrains.com/content/20-2417-1
Otherwise, you can check if the seller/dealer would accept the return without penalty, since lame dialogue probably does not fall under a shop's normal return policy. Hopefully, you can find a way to work this out.