[lincpimp]

Here I go, gonna try to cover each one...

1. I cant seem to fit the gear cover onto the top of the gears where it should go (i have the single motor mount). i can get it on, but it is really hard to, and once its on the spur gear keeps rubbing against it. is this part really necessary, or is it safe to run without out?

I never use the cover, but I try not to run in a bunch of loose dirt or small gravel... The heat gun technique already mentioned is most likely your best bet...
2. this really surprised me: i have two 3s 5000mah neuenergy lipos lasting 40 minutes with still 3.81-3.82v per cell in them! I charged them up fully before i went out, but once i was out it was proper hard running, speed runs and everything! and these lipos lasted for at LEAST 40 minutes. i say at least, because after 40 minutes it got dark and i had to go home. I hook the lipos up to the charger and each cell has around 3.8v still left in them!! not even close to the 3.2v LVC that i had set. This really amazes me.

The reason the cells read 3.8 is that after you let them sit, lipos will reagin some voltage. I would say that 40mins is great with your setup, you may get a few more minutes than that before the lvc kicks in. Now you see how good 6s lipo really is!
3. brianG's speed calculator says i should be going at least 50mph, but it seemed like it was going 40-45mph. no matter, still pretty fast!

The erevo handles speed well, so you may be going faster than you think...

4. I just have velcro holding down my MMM, and i did some pretty wild sumersaults and its held on fine, no need for zip ties!

I would suggest meking a hold down plate and ziptieing the mmm to that plate and screwing the whole lot onto the chassis. The cases do come apart, no way to get around that (unless you glue it, and I would NOT do that)
5. during and after my running session, i constantly felt the MMM, motor and lipos. during the entire session, the MMM and lipos were cold, and the motor was barely warm, even with continuous speed runs. amazing! i dont understand how people are getting such high temperatures.

What were the outside temps?

6. should there always be a spark when connecting lipos, cos there isnt anymore, but there used to be when i connected them a couple of days ago.

Mine spark everytime, but only after sitting for a while between uses. If I unplug the pack and plug it back in within a few mins it will not spark. The caps bleed down till they are empty while sitting...

7. how does the MMM let you know when the LVC is kicking in?

It stops you running and if you look at the leds while pulling the trigger the yellow light blinks. You should still have steering, but it is time to stop and charge.

8. as the lipos are used in a session, does performance decrease steadily, or is it a sudden drop in performance once they reach a certain point?

Lipos hold voltage well until they get close to 3v per cell. After you run for a while you will feel the performance drop right before the lvc kicks. I never hit the lvc anymore, as I just stop running when the performance drops off.

9. the next time i drive, i will run the lipos down to the LVC of 3.2v per cell. after i done this, when i get home, should i charge them up to 3.7v per cell? or should i just fully charge them to use next time? or should i just leave them as they are until next time? is there a way i can program my hyperion charger to just charge them up to 3.7v per cell?

Good to charge them back up, at least to half capacity. I have always charged mine fully and stored them, but that is supposedly not good to do... No idea why, maybe the cells do not like it... Never had an issue though.