There are some threads here about the differences between the different 1.5dci power and to some extent torque levels,if you do a few searches.
Aside from the cooler non cooler ,different intercooler and
1.5 dci engines 85/88bhp and above have redesigned piston crowns to accomodate the higher fuel pressures.
/DPF particle filter engines amd engines of a higherpower may have lower compression ratios than those of a lower power.,Yeh strange but true according to the published figures.
Something less publicised,since you ask about the injection system.
!.5 dci megane engines manufactured dec 2010,or later use a newer bosch injection system .
Before that and the vagaries of delphi system doesnt really concern me as mine was made in Jan 2011.
Im not saying nyah nyah or anything,but lots of googling should give you the answers you need and the 1.5dci specs arent as universal as you might think(especially since the 2012 stop/start version).