it also runs the edis/coil pack whereas the sierra one will only run the engine side of things, if that makes sense?

there is no pip/saw(sp?) signal generated by the sierra one even though it uses a crack sensor mounted to the flywheel
the 2.3 uses the same stuff but it's pointed at an angle and it runs balancer shafts in the sump so it's a little taller, but other than than (and the oil feed to the balancer shafts) the block and everything else is a direct replacement for the 2.0 lump

if you use a glaxy lump on the rwd car you have to tap the holes for the rwd mounts, same if you use the scoprio lump in a fwd car
the only difference mechanicaly otherwise is the size of the flywheel/clutch on the 2.3 as it's the same size as the V6/cossie although it's a different design, looks like a plastic bmx wheel so you can just restud your normal flywheel with the cossie stuff and away you go