unless you do some serious off-roading, I think the majority of R50 owners use the KYB GR-2/Excel-G struts and KYB Gas-A-Just shocks.
One thing for sure - the KYB Gas-A-Just shocks are (IMO) approximately 40%-50% more stiff than the KYB GR-2/Excel-G shocks (note, not the strusts) - and this is based on my common-person test;
I purchased both the KYB Gas-A-Just shocks and the KYB GR-2 shocks.
Compressing the Gas-A-Justs was noticibly more difficult to compress than the GR-2. The GR-2's were pretty "easy". I'm 5'11", 210lbs and the way I compressed them was to to push down on the piston rod as fast as I could. Using this "metric" , I figured the Gas-A-Justs were definitely stiffer.
I do 0.1% of my driving off-pavement (note, not off-road

). Sometimes I drive in the dirt or gravel, but I never go off-road.
I also have OME medium-duty springs (gave a settled rise of about 1" to the 124k mi suspension I purchased the car under). So, my impression is that the rear is definitely "stiffer" than the front - but this would make sense, since a lot more weight is at the front (engine, driver) and barely anything is in the rear.
To give you as best impression as I can of the difference between front and back (in the LEAST technical terms possible - because I don't know any technical terms):
When I go over a speed bump (those narrow ones, that measure about 1.5ft from the front to back, and about 4" high at its peak) the front will bounce (down-and-back-up cycle = 1 bounce) about 1.6 times (.6 is goes down again, but not as far as the first bounce, and returns up to normal extension). The rear will bounce 1.1times (.1 meaning it barely goes back down after the first bounce)

again, my apologies for the horrid lack of technicality contained in this post
