I have a buddy with a Dana 300 kicking around his shop... Would it be more worth it to install that instead and get the flip kit, twin stick etc?
No, cause flip kits always leak, and the shifters are so convoluted they seldomly worked right and are prone to binding.
On the other hand, were you to purchase a Stak 300 case that will allow you to reverse the drop of the 300 without flipping, then yes, definately a worthy swap.
In the end, the stak will cost you the same, if not less then the flip kit, but will work significantly better.
good luck