
I downloaded the mods and repurchased my Tier III IJN Kawachi to test out his SMS Helgoland conversion, a Kaiserliche Marine dreadnought and lead of her class that is nearly a twin for the Kawachi's turret layout to begin with. The most notable difference between Kawachi and Helgoland are the funnel arrangements. Kawachi has a gap between No. 1 and No. 2 of the three funnels while Helgoland has the three funnels evenly spaced apart. Helgoland also doesn't have tripod masts.

Helgoland-class battleship. Image courtesy of http://www.the-blueprints.com

The SMS Helgoland nee Kawachi in port.

Overhead view in port.

Ship in game, note the mod changes the flags to the WW-I KM ensign and adds a second to the mainmast but does not affect any other Japanese ships.

An ally in battle on the Russian Server.

IJN Kongou as herself in WoWs
After trying out the SMS Helgoland mod I had to test loituma's conversion of the Tier V IJN Kongou to the KM Bismarck. I already had a number of Tirpitz skins downloaded into my mod collection to the turrets and secondaries do not exactly match the paint scheme of the Bismarck mod. Sadly, the conversion doesn't work for me as there are too many differences between the real Bismarck and the Kongou such as the mod still keeps the Kongou's AA suite placement and only puts in a single quad German AA gun for decoration.

IJN Kongou as KM Bismarck in port.

Yes, the mod has the offensive Nazi national symbols on the bow and stern but no flag, the Japanese flag disappears is all.

Japanese dual-purpose 127 mm guns are retained.

As are the Japanese lighter AA guns.

A single German quad 20 mm flakverling is on Turret Bruno. It is for decoration only and doesn't fire in game. Game mechanics are not altered by the mod, just appearances.
loituma had one more conversion mod before he dropped off the grid on August 28, 2015. That is an incomplete Kongou - Warspite conversion. Since it wasn't finished, he gave up on it frankly, I didn't bother downloading and testing it against the in game Warspite.
If you never had the chance to purchase Warspite, or want a couple German battleships in game now while we wait for the German Battleship Tree to come out (on some yet to be announced date) you can try out these mods. Frankly, only the SMS Helgoland interests me besides the Aoba camo skin mod and the Farragut Hull A camo skin mod. I still gave loituma +1 for the effort on his forum thread.