In particular, for my case, I had to redrill some holes under my truck on the oil pan shield.
Application: you can't use the long arm rivnut tool for working in tight spaces, and these small manual tools are the right application for it. You need something to work upside down and in tight spots, this is the tool.
Rivet Nuts: I think it might be best to use those "cross" riv nuts rather than the ones that came with this kit. These worked fine, but I would go another way for thicker sheets of metal.
In any case, I'm hoping to find additional uses for the nuts that came with the kit - it might last my lifetime LOL.
The Step Drill Bit: that came with the kit - it did the job very well. Pierced through old bolt threads with little issue.
Case: actually holds all the pieces in decent fitness. Sometimes the case is too small as if some small child was able to pack everything inside of it, and my old hands can't figure it out. In this case, everything had just the right room to take everything out and put everything back in. It's not solid plastic, so I'm sure if I were to drop the case on the ground, everything would just explode. I will probably transfers these bits and tools to a more permanent stout case in the future. For now, it holds everything fine.
It's not inexpensive, but it did the job, and there are enough pieces, that if I were to use it for everything it was intended for, it would be a big time and cost saver.