Ordered up some kyb boots (sb103 and sb108) and although the rears were both the same (2-piece design) the two front 103's do not match eachother. One version (where the box was hand marked 'old design boot 1st gen') is a single piece with the bumpstop integrated into the softer rubber boot, whereas the other is a two piece design with a more 'plasticy' 'shopvac' hose type boot.

The one-piece is made in Korea and the two-piece is made in the USA (highlighted in pic). The bumpstops appear to be the same length, but the seperate bumpstop is like a dense white foam and is marked "HARD PB2103", whereas the integreated bumpstop is a dense black rubber and is marked "NA103"

question 1) Are the bumpstops a different density?
question 2) Which ones are known to have a more durable boot design, the 1-piece or 2-piece?

I am trying to figure out which boot to return.

 

the rubber one is the old design. they aren't made anymore. the poly foam bumper is new design. return the rubber one and get another new poly foam one.

as far as ride, i'd say the poly foam has a little more give and the boot design is much better. the rubber one will not last as long and have more of a harsh ride.