Kittoon, the short answer is, yes, it's possible to replace Martin's built-in electronics with a K&K Pure Mini. If you want to go completely without onboard electronics you can do that, and K&K also has some onboard preamps that you can use if you like.
http://kksound.com/preamps.php
What I'd suggest you do is first find a good local guitar repair tech, if you don't have one you work with already. With many of my performing instruments I have pulled out one pickup system after another until I've found one that I've liked in that guitar. Sometimes components from one company's products can be used with another's: EMG used to make a dandy little onboard preamp about the size of a postage stamp that they intended for use with their undersaddle acoustic guitar pickup, but which my repairman repurposed to power a number of different pickups in several of my instruments. I've still got one or two of those around.
So the onboard preamp that's already in the guitar might be able to be used with a K&K Pure Mini. (This is where it's crucial to have a repair tech who thoroughly understands impedance and all that other electronics stuff, which I do not.) And that's what I would explore if I was in your situation, before proceeding with anything else.
If you just flat don't want any batteries or preamps in the guitar at all, it's no big deal at all. Use the existing jack that's already in the guitar, and either leave the now-disconnected preamp with its knobs in place, or else yank all that stuff out. I've done it both ways. If you do remove the existing preamp you might want to have your repair tech plug the resulting holes where the preamp knobs once were - my repairman cut some plugs out of Indian rosewood and glued them into the side of one of my guitars that I still own and use. You can tell where they are if you go looking for them - it wasn't an invisible repair - but you have to know to find them.
Good luck with this. Please tell us what you end up doing.
Hope this helps.
Wade Hampton Miller