New TT or new Cart? Technics content

@chakster :  SP-10.  wow.  that is impressive!!

The TT has already been upgraded:
Feet, dampening, tonearm rewire, outboard power supply.  I've done it all. 

Really no interested in going back to separates.

So, cart or extra sub it seems?   

@ghdprentice 

For me, it's really about upgrading along the way.  I made a pretty big (for me) purchase with the hint6, so I'm going to keep all of the integrated aspects that it has.  I had separates before (prono pre), but the hint6 was way better.    

It's really about identifying the weak links in my current setup and trying to fill the gap with something basically at 150% of what I had (if that makes any sense).  With my setup I'm using the HT Bypass option, so I have the opportunity to run separate subs for 2 channel only.  During home theater, my setup can run 3 subs! 

Room treatment is difficult - I know it's an issue.  I've been banished to the finished basement for my listening.  It's a very large room 15x30x9 (15 across the front).  It's a general purpose space for entertaining so, I can't put up walls or anything.  Not sure if room treatment would be effective?  I'm sure it will help, but I'm not sure how much given the space.  

@mijostyn;

Thank you for such a detailed response!  

I have an older PSA S1500 (12" driver) now, and could potentially add another.  However, I'm wondering if there might be something more musical out there.  KEF Kube, or REL always get the recommendation.  The PSA specs are *way* better though..