4l60E and 4l80E questions with Gen III motors

[mahanian]

I searched but couldn't find the answer I'm looking for so here I am.... I'm putting together my build sheet for my Gen III motor swap into my 67 and I'm starting to chase parts, but I want to make sure I cover all my bases before spending the hard earned dough...so your help with a few questions is greatly appreciated!

Is there big differences between the 4l60E transmissions through the years?

Different clutches or gear ratios? Is one beefier than the rest?

Differences between car trannys and truck trannys?

Will they all bolt up to all Gen III engines? I'm currently looking at an LS1 out of a 2002 Corvette but I'm not 100% set on it yet.

Is the same true for the 4L80E?

How difficult is it to add a 4L80E to a block set up for a 4L60E, mechanically speaking...I know the harness is different and the ECM would have to be reprogrammed.

Thanks in advance for the help...