What parts are need to get my e-maxx BL?

[A RC Dude]

Thanks for the wellcome and info!
1. i think that my friend means something elts other than the idler but i'm not sure. as soon as he logs in he should clarify that.
2. i know that those diffs would be real good but i'm not even $100 sure i can get my e-maxx BL in the first place so i'm going to haft to go with cheaper diffs.
3. the thing is that the 33 shafts wan't fit well in my e-maxx with all those stock parts. so..i could eather get all the parts($100-110 worth of parts) to convert all the arms and everything to run well with the 3.3 shafts or i could just get the CVD's and be done.
3. i changed it to a four now lol my bad. and thanks. i didn't know if the plastic spur would hold up to to BL motor or not even with good mesh.