This car is a ball, but I commute some pretty rough rust-belt roads, and old fogey that I am, my back is starting to ache.
Anybody have any ideas for partial (and acceptable) remedy to firm ride? Tires?

 

This would solve the problem.

 

Softer springs

 

This is pretty much what the car is and what it was designed to do.
A flat-out sports car with no pretense to be anything different. My only guess is that you could try a more compliant tire, some sort of all-season deal, but that would would radically change the handling.
You can check the tire and wheel forum here, but Jim @ Tirerack seems to be a great believer in the OEM tires. Maybe a pillow would help.

 

If you haven't already, check to make sure you don't still have some of the spring spacers (installed for shipping from the factory) on your car. They will result in an uduly harsh ride (in addition to some other bad things, like diminished handling). Just a thought...

 

buy a TL?

 

register your vin, so we know what MY you've got.

 

You could run your tires slightly under inflated (30 psi). S0-3's seem to ride smoother to me than the stock S0-2's as well, but you do give up a little dry traction.

I've also heard a lot of good things about the Koni adjustable shocks. They will allow you to adjust between a soft and firm ride. You should be able to find a set for around $600.

Good luck, as this is probably the trickiest decision to make, as;

too soft = poor handling
too hard = uncomfortable ride