Hi, I've had my 2004 2door Echo Hatch since new

, and the rear end always bottoms out with 3 or 4 people in the car, its very annoying/embarrassing

.
Does anyone know of a way to fix this? I was thinking of getting new spring, but that wont help anything because they will be the same OEM ones are in now, and the car has been doing this since new and is only getting worse.
Are there any TRD springs that are slightly stiffer, but same ride height as OEM?
Any idea's would be appreciated, as I'm sure I'm not the first one to run into this...
-mark