My first post on POA. Finally decided to sign up. I'll apologize in advance if I'm beating a dead horse here but I'm looking for some info and ultimately opinions of other plane owners. I've recently purchased a C172M and am a student pilot. I have a (working) KT-76 transponder and am trying to decide what I'll do for the 2020 Mode-S mandate. My first thoughts were to keep my old KT76 and get a UAvionics SkyBeacon guide-light ADS-B out device but then I came across a possible slide-in replacement such as the KT-74. This would be a bit more expensive but it SEEMS like it would be better. That's where I'm curious. I do not have any WAAS-capable stuff and don't have any immediate plans to get that so ADS-B In right now isn't going to be an option. My first question, is what would I have to gain by actually exchanging my transponder with an ADS-B out capable one? Also, is the replacement "slide in" in the sense that it's a somewhat quick install process? Anyway, any info is helpful. Thanks in advance.