I starting playing with mods in 1.3, cause in 1.2.5 I wasn't smart enough to know how to install them XD and I downloaded them from minecraftdl too...
I started coding in 1.4, where I word-to-word copied a tutorial on youtube and added a textureless block to the game. I felt so proud.
About BigReactors support, I already have enough to do that I haven't been doing. So no.