Hi all,Am looking to get a Hikvision DVR and upgrade my old analogue system to turbo HD - thinking I will get the colorvu cameras with built in siren. I've got a bit confused with the choice of DVR and hoping for some help...Other than some facial recognition stuff, what exactly is the difference between the K(B) series and the M series - i.e. iDS-7208HUHI-K1/4S(B) vs IDS-7208HUHI-M1/FA?I can find loads about the former but very little about the latter. Did the change from K(B) to M bring improvements to the Acusense functionality etc? Very few places seem to stock the M series... Any thoughts as to why?Any help would be much appreciated!!!