the old E34 530 was stiff but well connected... when we went to E39 sport, it was firm but not as firm as E34... the 4.6is was further departure from the E34... 4.8is is on par with 4.6is... the "is" is as sport as they come - the 4.6 had air on the rear only and the 4.8 is air all around...

i suspect that your specimen has completely shut suspension components... besides, some pieces might not be interchangeable - you would need to cross-reference the RealOEM for fitment...

I would suggest finding an E53 on a local lot with "good" sports package and test drive it, just to confirm your course of action...