different companies call them different things, you are best to know the spec of the turbo you want rather than asking them for a stage 1 etc as it will be different depending on who you go to
as a rough guide
superspool is a 55trim compressor wheel, standard 62trim turbine wheel
gti-r is a 60trim compressor wheel, standard 62trim turbine wheel(rog, poweritalia call this a stage 2 hybrid as does barbz at torque italia but cr turbos would call this a stage 1 hybrid)
largest common hybrid is known as either stage 3 or gti-rs
this consists of the 62trim compressor wheel and is available with either the larger 76trim turbine wheel (rog, poweritalia's stage 3) or with the standard 62trim turbine wheel (barbz, torque italia stage 3, don't know if cr turbo's have a name for this one)