Ok - so I get a creaking/groaning noise pretty much at all 4 corners when going over bumps, etc. slowly (so backing out of the driveway, etc.) - I tried reseating the springs but that didn't seem to do anything...

Any ideas? Does something need to be cleaned/lubed?

This is with the stock suspension in an 02 WRX wagon

 

You are still under warranty -- take it back to the dealer and have them properly torque and lube the suspension. I also had this problem on my 2002 WRX sedan, it was a 15-minute fix. Do it NOW -- if you let it go for too long, you can cause suspension damage, according to the mechanic.

 

Most likely it's the stab bar bushings.

 

you mean front sway bar or something else?

 

Stabilizer bar = sway bar = anti-roll bar. Front and rear it sounds like.