Well then, it has been some time and I have been activly working on Dungeon Maker the past few days.
The version has moved from UDM2 to Unreal Dungeon Maker 3. Dungeon Maker 3 now supports layers for building into the air, or going into the ground to create very advanced and complex dungeons... or just dm maps with underground bases!
Anyways thanks to alot of help from gigyas, Head Rebel and everyone I probably forgot

I got a new exporter with a better algorithm!
The new exporter.. 1600 brushes are being exported in about 40 seconds ( in the past 10 minutes ) and imported into UnrealED in less then 6 seconds ( in the past 20-30 minutes)

Proof?
Sure, this is the 80x80 fullgriddungeon.udm that matrix made for me a long long time ago:

Dungeon Maker 3 is still under construction, but will soon be ready! I hope you enjoy the news so far, and I will keep you posted ( fine.. changelog too )
Version 3.1:
+ Fixed the map sharing page, found php errors in the downloaded files LOL.
+ Fixed the layers, UDM now supports 41 layers to build up and down!
+ Fixed a bug at exporting ( double begin map and level info ).
+ With help from gigyas, I made a new algorithm for map exporting, faster & smaller!
+ Made map exportation more strict, the slightest error makes the export fail, the end.
+ Added debughelp to the exporter ( custom tiles etc )
+ Changed every tile to be compatible with the new exporter.
+ Without Head Rebel it wouldn't be as it is right now.
+ Added layer functionality ingame!
+ Hacked the UMX filetype thanks to support from TheDarksider!
This means Dungeon Maker can now play Unreal songs!
+ All tiles are now smooth ingame, no more lighting bugs.
+ You can select a song for your map ( but only with UnrealED limitations ).
+ Added an @ boot check to download missing dll files etc.
+ Added new commands for Z level at actors and brushes.
+ Fixed issues with clearing your map.
+ Added special layer options, merge with ceiling or every layer new floor.
+ Added more cleaning options such as clean map info ( song, layersettings etc ).
+ Created a new map saving algorithm, I can now add as much information as I want
which stays backwards compatible, ud3 is probably the final savefile.
+ Made the upload map compatible with the ud3 format.
+ Created a new way to merge custom Z values with the layers ( in the tiles ).
+ Fixed the actor template placing, it now works on all layers.

Please note that all tiles are being rewritten so once UDM3 is out, UDM2 loses compatibility with them.
I am continueing here, thanks for the comments ^^
The first multi layer map test ( there are multiple settings )


NEW! I added support for Z calculation at the tiles, I can now give it the finishing touch and release it.. tommorow?

Ingame:

Every layer new floor mode:


+ Fixed the actor template placing, it now works on all layers.