Hello!
Can someone recommend a model in each division (Ground, Air, Water-Military and Civilian) with most parts in their group .Also , more difficult is better

I think this is the biggest plastic kit on the market a 1/35 scale Dora Railway Gun 5 feet long and over 3000 parts

http://www.scalehobbyist.com/catagories/Artillery/AOS00077658/product.php?kw=dora

I recently finished Dragon #6301,Panzer IV. Vorpanzer,it has over a 1000 parts and as you know a Mark IV just isnt that big,that's a lot of parts to jam in there.It includes Magic Tracks and lots of PE .It really builds up nice for all those parts involved.

Check my photo gallery to see it

Tamiya's new 1/350 Yamato is big. With a lot of parts,also Hasgawa's 1/350 Akagi has a lot of detail.

Trumpeter has many 1/32 aircraft which lok pretty impressive

what about this one from Trumpeter...



It has 923 parts Im thinking of maybe building this for the AFV/APC campaign, maybe.

More than 1000 pieces.

big thanks for information

Just a guess for aircraft, but the Zoukei-Mura AH-1 or P-51D, or the Trumpeter P-47D, full engine and interior, lots of detail. Price is almost as high as the parts count. In Naval subjects, the 1/350 scale LHD kits, Wasp and Iwo Jima offer tons of detail at a high parts count.

Here's a second vote for the Dragon 6301 Vorpanzer. I'm currently doing a build log here: https://armorama.kitmaker.net/forums/194629&page=1

I don't own it, but I've read a lot about the Tamiya 1/32 Mustang P-51D, which sounds awfully complex.