hi everybody =)

hi all, me and my 5yr son are both Wii-tards but he's taking the step in2 DS land D'oh!.
all this DS DSI XL ect ect is killin me!!! not sure if im ordering a bking or watching a crime drama lol.
i have looked around stores online ect, could anybody make it simple what the differences are please.
are they all 3D? i looked at 1 in a shop and the 3D was awful like bad acid.
do all games work on all?
can they all be soft modded oops! flashed on here i think.
i think he wants DSI XL (what is it) wen i look it comes as ds 3d?
he needs an xl as he's got cataracts in his right eye so wen he's playing the Wii everyday he wears a patch on his good eye.
hence my thoughts about 3D???

hope this makes sense =)
thanks
yrs zappa