Audio Note members re going from M3 Line to M6 phono


I am considering selling my AN UK M3 Line and purchasing the AN M6 phono. Because I use a Denon DL103 MC I will also have to get an SUT. There is about a $4000 cdn difference in the value of my M3 and the M6.

Or should I just spend the money on a Audio Note Phono stage for the M3

What about the SUT? Or forget the SUT  and just spend the money an a good MM cartridge instead.

My TT is an LP12 with the Rb300 Audio Note arm.

Thanks in advance for your suggestions. 
128x128pkvintage
If these are your choices with no other options to be considered, I can only suggest that there are several fine MM and MI cartridges that more than hold their own with the Denon DL103.  So, by choosing one of those, you can avoid the considerable expense and complication of adding an SUT that can keep up with the other gear.  That's if cost is an object.
Not sure this would work with your table and arm but the Dynavector X 20 series comes in high output.  I am sure it would truly shine on the M6 phono section.
Get a Schiit phono stage and save thousands compared to the cost of an AN. And with the hi-gain option on the Schiit you don't need an SUT. Stick with the AN M3 line stage!
Update... I purchased the M6 and will complete the synergy with the AN SUT. Thanks for the replies folks. 
Update.... 

I am very happy with my purchase. M6 Phono with AN SUT 2 Denon dl103. Sounds glorious. 

Thanks for all the replies.