Brown stripe springs for both the SWB 280GE and SWB 300GD.
You probably have a tired spring. G's need a little help getting it up sometimes.
On that note, if you can wait a few months, we will have a boatload (quite literally) of springs coming from Germany that are made by SACHS. The springs are less expensive than the MB springs, are of very high quality and the rears come with the anti-vibration hoses already installed, which is an added bonus. As you know, the MB springs typically come with one, two or three stripes painted on them, with the latter being the most stiff version. SACHS springs are made to the two stripe specification, which is right in the middle stiffness wise.
Give Steve D. a shout tomorrow and he can give you the details. 1-866-580-3586