I love variety, but sometimes it gets confusing with all these PIDs. What's the difference between:

GM.DYNCYL_AIR_DMA
GM.DYNCYL_AIR
GM.CYLAIR_DMA
CALC.CYLAIR

or

GM.CHRGTEMP_DMA
GM.DYNAIRTMP_DMA
GM.IAT

or

GM.MAF
SAE.MAF

any tutorials on that?