finally getting ready to do some shopping for my engine and tranny swap.

specifically though, what are some things that i need to look out for as far as the year models and vehicles that i find the engine and tranny out of?

i have a 2000 ecsb with the 5.3.

i've heard that after 03 (i think) the fuel lines went from return style to returnless.
i also know that somewhere in there they went from drive by cable to drive by wire.

i'm looking for as little hassle as possible, but if i got a newer engine, what could be done about these changes? is a matter of swapping the fuel rails, or is more in depth?

i would like to keep the drive by cable set up. also as far as the driveshaft and xmember for the 80e. i've read that you can just use the ones from a 2500 hd (as long as its ec) and the length and fit would be good. any light shed there would be great also.

thanks guys, i plan on asking more questions too as i get deeper into the swap.