This morning Caveman, Omulet and I tested extra mods with the current world. We went back to the original spawnpoint and travelled into the other direction which was still undiscovered. After appr. 800-1000 blocks we reached a new biome with all the new trees, bushes and flowers. In the npc vilage we found 2 appiaries (hive to keep bees) and some wild hives.
Omulet found the new ores (copper and tin) in the vicinity, which are added by and required for Forestry.
Caveman has also tested the Sphax texturepack for the added mods and most blocks are supported.

Apparently we can have best of both worlds; Â*keep the current world and add the mods to enhance our gameplay.

If anyone has any suggestions for mods post them here, so we can test them.