I have a Lowrance Mark 4 Chirp in my 192. I bought it primarily because it was on sale (in my budget) and included a card for all NA inland lakes. That was important for me because I primarily use it for navigating on unfamiliar lakes and for accurate speed and depth. I'm not much of a freshwater fishing fan so I don't really use if for a fishfinder. It does seem to do a decent job of showing underwater obstacles.
As for the install, I aped this thread
https://jetboaters.net/threads/installing-a-lowarence-elite-5-on-a-fsh.7785/ since the hulls are the same agross all of the 19' boats.
My mounting location and method is shown in this thread, but since you have an FSH I probably won't be particularly helpful
https://jetboaters.net/threads/the-...et-boat-today-thread.2661/page-29#post-155258
You are probably going to want to invest in one of the two steering enhancement designs. I have Thrustvector XVs. I'm sure the Cobra designs are great too.
I bought an off-brand boat buckle-style retractable strap system, but I don't recall the name. I think any of them will work if you buy one for 3500 lbs or greater. You might couldget by with something lighter, but I'm a conservative kind of guy.
Lot's of people are going to suggest you get a box anchor and they do work great. However, they are very expensive and you are going to eventually lose it unless your lakes have very clean bottoms. For that reason, I just use a cheapo slip-ring anchor and chain. I'm on my third one, I think. I rarely have problems setting them, although you probaly have to pay more attention than you do with a box. The ones I buy at Academy are a little too wide to fit in the 19' anchor locker, so I narrow them up with a cut-off tool and re-galvanize each tip.
As for other things you will need, unless you are a stereo kind of guy, keep your head unit, replace your speakers if they aren't the Polks and add a small amp. You'll get a lot of bang for your buck and will be able to hear your music over the engine.
Put in some led's if you ever plan to be out after dark. They really help with moving around the boat when you are anchored and they just look super cool. $50's of awesome. Mine an other's installs in this thread
https://jetboaters.net/threads/post-your-yamaha-190-192-lighting-upgrade-pics.9642/#post-165016
Get some Seadeck as soon as you can. It's great.
That's all I can think of at the moment.