I am just about half way through putting one of these k5 kits together, chassis and axles, and I have had a few minor issues.
**step D-1 on page 40 and 41 in the manual off vaterra's website shows the rear frame rails lined up with 9 holes for chassis adjustment. The rails that were in the kit have 10. I had a lot of trouble getting things lined up for chassis length. After looking at page 41 I got the frame rails to the proper length, but I had the center skid plate lined up to he rear hole which was too far back for the body/wheels/bumpers to line up right.
1- the skid plate did not fit into one of the chassis rails. Wasn't out by much, I used an exacto at a right angle to scrape a little off the top and still had to use a moderate amount of force to get it in. May be just a one off of the rail out of spec, because the other side fit snugly with no problems.
2- the king pins, or screw and flanged washer in the front uprights. I had to loosen off the screws on top and bottom ~ 1/2 turn to get the steering to turn without binding. Not an issue now, but I am sure at least one of those screws will fall out at the most inconvenient time out on a long run somewhere.
3- the set screw pins in the wheel hex. They were all a little tricky to get lined up right, and on one of the rear hexes I leaned my hex driver a little too hard and snapped half the threads off the pin. I do like these pins that use the 2.0mm driver instead of a 1.5mm driver, but the sidewalls of the set screw part of the pin is a little thin. You will have to be careful if you are using a decent set of drivers and not just tiny Allen keys. I was able to make the broken one work, but I will have to get some replacements. It is nice that the wheel hexes fit snugly onto the outdrives, but the the set pins will not thread in until the pin is just through the outdrive and into the other side of the hex which was the main cause of trouble for me.
4- axle diff shims. It looks like two small .5mm shims or something. In the little addendum instructions they came with it showed one on each side of the axle ring gear. I wasn't sure about this and I put them both on one side to hold things tighter against the pinion. Everything seems to mesh good, but I don't know for sure it might be able to use some more.
5- after going through and assembling all of bag D, I was short one 3x10mm tapered head screw and had on extra 3x10mm button head screw. I went through the chassis and could find any wrong placement of any screws, so it must have been a small oversight in packaging. I am sure it is a rare mistake, luckily I had a pack of 3x10mm TH traxxas screws handy from another project.
Other than these minor bumps along the way I am impressed with this chassis so far. I may have to read some more forums for tips on this thing, this is the first thread I started reading while assembling this beast!