I can answer a few of these questions, although a lot of this is personal opinion, so you will get people that give the exact opposite reply. Do your research and decide for yourself.
I run full synthetic in everything. Red Line Lightweight Shockproof in the tranny, Red Line synthetic oil in the engine (frame). The Shockproof is light years better than any non synthetic. It coats all the gears and timing chain so much that you cannot get the stuff off the internal parts without pulling the engine. It is quite a mess when you do pull it, but the lubrication properties are astounding, and unparalleled.
We only use 1 qt in the engine (frame), to avoid hydrolock, and ours have all worked fine for six years with that. When you pull the dipstick with one quart you will notice that the level is halfway between full and the end of the stick, which is fine. Fill the tranny until you either pour excess out the fill hole or see it in the sightglass, either way it only takes one quart (Shockproof is $10/qt.)
Engine is is poopy, unless you have an aluminum cam cover. Anything, ANYTHING with water in it at all will rot ANY magnesium cover, powdercoated or not. Either swap your cover or run Evans. Black Widow or Boomer has aluminum covers.
I have a moto 5th, and actually started a thread when I was undecided about installing the gear, and I love it. I really don't need anything more than that, and the ratio change is unnoticeable, just like in the lower gears.
D&M refers to Diagnostic & Maintenance kit to modify the air/fuel map and parameters. If you really feel you need one, then pick it up for ~$350 (cable and software). Cable is serial only, not USB. Many people seem to get into trouble fiddling around with one, so you have to decide how much you will really use it. It depends on your mods and how tuned you really want to get. With the D&M and a dyno you can dial the AFR (Air - Fuel Ratio) to exactly what you want/need for your specific modifications. In my opinion you need someone who is at an expert level to show you how to use it, because it can be tricky, and the wrong adjustments can render your bike not running and/or needing a rebuild.
I didn't address the vent hose because I didn't understand the specific question....
Just did some searching and have some questions
Mods to Cdale I may own: HMF pipe and ECU programed (blaze/moto I belive)
Trans Oil: Calls for .75 Quarts. I want to use Maxima 80WT, also is it safer just to put in 1 quart?
Engine Oil: Calls for 1.5 Quarts. I want to use Maxima 10w 40, also could I just dump 2 quarts in?
Coolant: I have a sponsorship from engine ice. Is it safer with the Mag heads? (i belive my dads is PCed anyways)
Reason I want to round up the quarts is because all my other quads is accualyl safer to do so. But from what I have read Cdales are kinda touchy.
Ok more questions......
Gearing: I know 5th gear is really high, I was reading about another gear intall to make it not such a drag into 5th. Right now it has 1 tooth up the front and a stock rear (belive thats 14/39) Would a diffrent 5th gear be needed since I will be drag racing accross fields, riding the dunes about 3 times a year, and praticing MX maybe 10 times a year on a very tight indoor track where I only hit 2nd gear on my 400ex?
Vent hose mod for oil. What is the accually mod? Just moving it to the back so it dosen't leak?
D and M for the efi? What is it? Searching dosen't bring it up since it wont search for only single letters and "and"
Thanks let me know anything else I may need to know