Just note, this is all my opinion and what I have inferred from my own experiences and reading!
This really depends on what you want from your implant and when you want it.
I have a spark, and I’m waiting for the Public release of the Flex One. ( Date unknown )
I’ll be leaving my Spark in, and I will use both.
As far as the applet capability:-
currently developed and being tested
in development ( as far as I am aware)
SOOOO I want to answer this for you, But the disclosure of this is not my place to do so.
Amal will release this info here when he is happy to.
There are no release dates yet, so I’m not sure how long you are willing to wait, so basically if you want one now get one, if you are happy to wait for the Spark 2 then…
I don’t know whether the Flex One or Spark 2 will be released first; Nor am I aware of the cost of either.
Put it this way, IT CAN BE DONE but there are many technologies and ways to do it, I will give you a generic link for a youtube search, there are more arduino based methods ( Using NFC ) but amongst them are a few RFID ones, It all depends on HOW you want to do it.
Amal has published a book called RFID Toys: Cool Projects for Home, Office, and Entertainment (ExtremeTech) I bought a copy and is a good read.
It has some great info, and most of it is still relevant ( there are some dead links and some newer technology) it would be a good reference for you and there is a guide on how to make your own vehicle entry system.
Or check out this thread
One of the many projects I am working on is a simple, cheap, low power vehicle access system ( Lock / unlock ). I am very confident I am going to get it, I just need the time ( and some parts) to finish it. Keep an eye on the projects section (https://forum.dangerousthings.com/c/projects) for somebody elses solution or mine that I will update (RFID Vehicle unlock and start for CHEAP !?! ( R&D Phase ))
I’m not sure if you are aware But Dangerous Things also have a YouTube channel
I HATE social media, so I haven’t been on the following, but hopefully there is some more info on there to help.
One of the community members on here @Vicarious has a YouTube channel (https://www.youtube.com/user/ACKspacenl) with some good use examples
Also a reseller ( digiwell ) quick use case montage
I hope that answers your questions