My no brainer mod is like most of the other things I recommend, most won't see the value immediately and sometimes never, but the value is there. My mod is you. Go drive it, go learn how to drive it, go learn how to make it get you where you want to go before you start building it. Start on the easy stuff, learn tire placement, learn momentum and how to use it correctly. When that no longer gets you where you want to go, then start building the rig and the build plan at that point will be very easy because you will know what you need and won't have to ask anyone. Don't fall prey to the concept of building the rig instead of building your skills. That is pretty much doing it backwards and I've wheeled with a bunch of that type and they are no better today at navigating the trails than they were the first time they got behind the wheel.
They are easy to spot, they have the biggest rig in the group and struggle the most.