hey whatsup welcome to the forums.
it seems like you know most of what you need to make this BL but ill try and answer your questions.
1. are you talking about the idler?
http://www.rc-monster.com/proddetail...03idler&cat=17
2.maybe these will be better
http://www.rc-monster.com/proddetail...zerdiff&cat=17
3. i would say to not get cvds... get the 3.3 driveshafts as those are PLENTY strong.
3. (you have two number 3s. lol) you dont need a aluminum spur just be sure that you have a good mesh and you will be fine.