First let me say this is a great kit from Lego. I have built or helped build many of my Kids Lego sets over the years, but this is one of the ones I bought basically for myself to build. This is a challenging build for sure, but if the directions are followed exactly how they are written you model will turn out great. It took me approx. 20 hours of work to assemble the kit spread out over 5 days.I have read a lot of the negative reviews about missing pieces, etc. Let me say that I have never found a Lego set to be missing pieces. Now, maybe I'm extremely lucky in that regard, but more than likely its because I'm meticulous when I build things and check and double check assemblies before moving on to the next step. You really have to pay attention to which parts you are selecting during the build process, especially with this kit since you need to open up multiple bags at one time and have hundreds of parts jumbled together, unlike most Lego sets where you open bags in order, one bag at a time. Many pieces resemble others, and if the correct parts aren't chosen you are going to think you are missing parts at the end of a build section. I suspect that is what a lot of people are doing that say they have missing parts. Believe me, nobody is perfect, and I make mistakes as well when building, but by checking yourself as you build you can avoid a lot of headache later trying to figure out what is wrong. I'll give you a couple examples of errors that I made when building this car. One was an easy fix - when I got near to the end of box 3 I discovered I didn't have one of the black pieces in step 504 that was to be one of the paddle shifters. I looked through all of the pieces I had left from that box and discovered that instead of the black piece I had a gray piece exactly like it left. That told me right there that I had screwed up somewhere earlier in the build and had selected a black piece earlier instead of a gray piece. I could have complained to Lego and told them they screwed up and gave me the wrong piece, but instead I figured I had made an error. So, I started going back through the pages looking for steps that had the same piece, but only in gray. Well, when I got back to the section where the seats were build sure enough I had inadvertently picked a black piece instead of a gray piece for one of the seats. It took about 10 minutes to disassemble seat to swap the parts. Result - no missing piece, builder error.I have also read on here complaints about the gears not working and the car not rolling because the front and back wheels work in different directions. If you think about it, do you really think Lego would put out a set where the wheel worked in opposite directions or the gears didn't work and not have almost every single person building the set not complain? Bottom line is if your gears don't work or the front and backwheels work in opposite directions you screwed up somewhere in the build. I can attest to this myself as this was the other error I made during assembly. When I was assembling the front differential gears I wasn't paying complete attention and flip the front differential gear housing from what it showed in the manual. If you're tired or rushing through the build it's an easy error to make. Once I had the front drive train installed the first thing I did was to check the rotation of all four wheels. Sure enough the front wheels were rotating in the opposite direction of the rear wheels. I knew almost right away what I had done, and when I compared what I had built to the drawings on step 222 in the manual I confirmed it was my mistake. It doesn't seem like a big deal how that housing goes in, but if it is installed with the gear on the housing to the right instead of how it shows it should be on the left, the front wheels will work in the opposite direction that they should.Another review I read complained about extra parts being in box one. Boxes one and two are rather large and can hold a lot of parts. Boxes three, four, and five are a lot smaller and have limited space. Those boxes are already stuffed with parts, and the last thing you really want is to have plastic parts crammed into a box and be deformed from being put in there like that. The best thing to do is to add a few bigger parts from those boxes and put them in one of the boxes that have more room, such as box one. That is why there are a lot of extra parts in box one, not because they screwed up. Also, when you get to the various pages in the manual where you are starting on a new box the first picture on that page will show you what the car will look like when that box is complete, what bag numbers to use, and it will show the extra parts from box one that you will need. For example for box three on page 260 it shows the car as it will look once that box is complete, it shows you will need bags 3, and then it shows 8 of the one black pieces, 1 of the black rectangular pieces, and two of the long red pieces. Those are found in box one as I mentioned, because again there is no room for them in box three. So again, the loose parts in box one and the parts in unmarked bags are for other boxes.A couple of the pictures I attached show my finished car - it really is beautiful what Lego has done with this. The front boot opens, the spoiler goes up and down, the transmission works, you can put the car in neutral from the shifter in the center console so that the engine can be disconnected from the drive train, the scissor doors open, the steering works, etc.In regards to missing pieces - almost 100% I can tell you that if you think you have a missing part or parts it's because you didn't build something correctly and/or used the wrong parts when building it. The one picture I attached shows what kind of pieces shouldn't be left over, not only in this kit but in other Lego sets as well. It's the picture with five pieces in it. Those are not the kinds of pieces you want left at the end of a build step - if you have those kinds of pieces left over you probably screwed up somewhere. In another one of my pictures it shows about 23 little pieces - connectors, single tile pieces, etc. These are the kinds of parts that are usually extra in kits, and the ones shown in the picture are exactly what I had left after building mine. Actually I was surprised I had 5 of the black connectors left, but there were hundreds of those in the kits (actually 511 per the back of the manual) so you can expect several extra of those.Bottom line is this is a beautiful, extremely well thought out and designed model. I don't work for Lego, I just admire their attention to detail and don't like them getting a bad rep for what is almost completely and extremely likely human error on parts of the builders.