Digital BW, The Print

I am currently printing with an 1160 using carbon sepia piezotones 
and an iQuad profile on Photo Rag.  I love the look of the prints 
but the printer is becoming fussier every day.  I can only print 2-3 
prints before horizontal banding shows up.  I do cleaning cycles and 
Windex and then can print again.  But the banding always shows back 
up.

I would like to upgrade the printer to a more reliable and durable 
one since my print volume has also increased.  And I would like to 
keep the look of the carbon sepia piezotones.  Going to a wider 
model would be a plus.

I have tried QTR on my 2200 and Ultrachromes using canned profiles 
but could never get the blacks and the "pop" of the piezo inks.

Any suggestions on my upgrade path?  A 4000 with piezo inks and 
Studioprint?  The same setup except using QTR?  Ultrachromes, QTR 
and custom profiles?  Is the new 4800 be a possibility?

Any suggestions or advice would be greatly appreciated. 

Thanks,
Jenny