i have used oem boge , oem sachs , sachs sportkit and boge turbo gas..from my experience this is what i found
boge oem = very comfort might be soft to the young blood
sachs oem = slight harder than boge like 10%
sachs sportkit = the most comfortable than the rest of sportkit among al(compare bilstein,koni,hnr ).but yet still not very low compare to others.very good ground clearance.still having it on my e46.is most likely like m-tech spec.i think it is also call oem replacement for m-tech sportkit.
boge turbo gas = oem replacement for m-tech absorber.slight soft then sachs sporkit absober.very good to pair up wit any lowered spring.even wit the most sucks lowered spring (some silver spring that claim to be made in australia which local company is selling it.i guess u guys know what brand i m referring to,without me spelling out).very comfort n for giving rebound.
eventhought sachs oem n boge oem made from same company that is ZF.but they work differently.the damping n rebound are not the same.i belief the internal parts as well.thats why there is different in price for this two as well.also the reason why ZF still producing this two different brand.dont u ever think why would some the company would want to increase their production cost by making two brands if they works the same?
thank you...