I'm on the fence between 2 great handling cars
 

Of course one of them is the newest Miata ND because I love the way they redesigned it. But it has a fair competitor; the BRZ/FRS/86. As you would expect, I don' care too much for the 4 bangers (hence why I'm on this site) but I've had trouble finding a DIY kit for an ls swap on the miata. The other option is somewhat expensive as expected but lacks the street credit that it deserves. I've been fasinated with miatas ever since I visited California in 2015. Where they would race miatas down a side of a mountain with no guard rails, inches away from plummeting to their certain doom. Anyways, the decision is still yet to be made on which route I'd like to go. It would be super helpful if someone could point me in the right direction of a ls kit for the Miata ND!

Flyin Miata has done a swap or two on an ND Miata but it is darn expensive.
You can check out their website or give them a call and they can tell you if it is practical for you to do your own swap and what it costs for the parts.

They havnt released a kit for the DIY guys yet. I talked to them and they said they are hoping to come out with something by next year.

For me, the comparison between a newer Miata and a BRZ comes down to the Miata being a convertible.
If you want a convertible then the Miata is the only choice.
If that is not important to you then you will have to decide which you prefer.
Without needing to do a swap a used BMW Roadster convertible comes to mind because it is available with a 6 cylinder engine without the need to do a swap. A very reasonable choice if you want to be able to have a mechanic do any work on the car.

If you are really set on doing a V6 or V8 swap and are considering a Miata you should look at the early NC Miata (2006-2008) because there are a number of successful swaps documented here. Swaps get more difficult with newer model cars because of all the electronics that are integrated into newer cars.

Personally, I consider the 1999 to 2001 Miata as being in a sweet spot for a V6 or V8 swap because of the minimal electronics but still being able to easily find a nice clean rust free car to utilize. In my mind a V8 Miata is a modern day version of the early 1960's AC Cobra with a soft top that actually seals up and air bags for a bit more safety in case of a wreck.