Go over it well. I found only a couple places lacking loctite, and that was the screws that go into the alloy cross braces that hold the chassis braces to the wing mount and front end. The diffs should be fine. They come with good diff fluid already in there. No need to tear them down unless you feel you need to change the handling. It is pretty solid out of the box. The only little things I have done were to place small rings of fuel tubing (about 1/16 inch thick) in the outdrives that hold the 2 center driveshafts. That will limit the play and rattling that they come with. Also, check to make sure your steering servo is tight. The back 2 screws in mine were too long and wouldn't tighten all the way down. I added a couple washers on top of them so they tightened better. If not, you may have loose/asymmetrical steering. Make sure you take the time to break in the engine properly. I am on my final "break-in" tank and will be tuning it soon. Even so, this thing is fast even when running at 160F.