These are all the reasons we stay away from the term "lift kit". Another thing is most lift kits are advertised at pretty low prices and include a fraction of what you really need, especially when starting with an old truck that has a lot of old and worn parts. The other side is we've come a LONG way since the big companies "lift kits" were designed and I don't think any of them have thought about a straight axle GM for a couple decades. We have. A lot. And have the experience with a lot of different builds for different purposes to steering you into what will work for your truck and what you want to do with it. For a budget suspension a cheap "lift kit" can be a good starting point to at least get you some springs and shocks and ubolts but from there we need to add some parts to get it really working right and staying together. And the more stuff you try to mix the more confusing it can be for everyone. If mixing and matching truck parts is a hobby and reading truck forums is what puts you to sleep every night you will likely have some success. If you think about other things more, working with one company may be a better choice.