The best suspension upgrade for the money would be the ST sway bars, in my opinion.
I'd get that before spending a penny on any other suspension stuff (apart from fixing broken or worn out components).
After that, I'd invest in a good alignment job (yes seriously), it makes a tremendous difference.
As far as shocks and springs, if you want to keep the TEMS, you cannot go wrong with new stock Toyota shocks. The only other TEMS shocks are made by Tokico and it's are a crap-shoot what you actually get and how long it lasts (do a search for Illumina shocks, you'll see).
For springs, lots of options out there, and it is very dependent where and how you drive your car. For a daily driver, shortening your stock ones is as good an option as any (flamewar here we come
).
Best of Luck.
