So I wanted to follow up on my own thread, in case potential or new owners find it in the future.
I put just over 100 miles on my GT (mostly because it's been raining a ton down here the last few weeks), and I think I have a good feel for the bike now. So, to answer my own questions from the first post in this thread:
1. Brakes: the rear brake is good, the front brakes are... ok. They do feel a bit "wooden" as some say, but what it really is is a lack of initial bite and a not-too-aggressive feel. I think for a sports touring bike that is meant to be easy to ride in all weather conditions, that makes sense. I can live with them, but I'll likely upgrade the pads all around in the next few months. I'll eventually do braided lines, once some more options become available.
2. Service manual: you can order one directly from Suzuki here: Genuine Suzuki Manuals
3. Cross-reference with other models: there is a lot of cross-over with the 22/23 GSX-S1000, but I haven't found any easy to follow lists. It's a case by case basis, you can compare part numbers in the parts catalog.
4. Air filter: TBD. I'll edit this response once I talk with Moore Mafia.
5. Exhaust: TBD. I'll update this soon.
6. Vibrations: there are definitely vibrations, but they're not terrible. They're most noticeable to me in the ~5K RPM range, but they're pretty high frequency and don't make my hands or feet go numb. I actually kinda like it because I can feel the engine a bit and learn to understand what it's doing. The stock exhaust is so quiet that the wind noise in my helmet drowns it out, so feeling the engine isn't a bad thing.
Now random thoughts... overall I really like this bike. I installed a number of EvoTech parts on it already, so it looks good and I learned how to take most of the fairing apart. It comes off surprisingly easy (and in big pieces) considering how much plastic there is to take off.
The power is pretty nuts... I'm still in the break-in period so I'm not going crazy with it, but let's just say that at 5K RPM things start to happen really fast, and by 8K RPM you're thinking "there is no way this will keep pulling"... but it does. The power is super usable too, it's very tame when you want it, but it can also be aggressive. It's not v-twin torque, but it's still very meaty. I keep it in A mode, I don't see a reason not to, the other modes are fine, but honestly A mode isn't the least bit scary, it's just responsive, how I like it.
The LCD display is nice, I prefer it in dark mode at all times. My only complaint is the Suzuki phone app... it's complete garbage. As a result I can't use navigation on the LCD and have been using my phone. I'm considering a Garmin Zumo XT2, that may be a purchase once I get this bike uncorked and tuned.
A small thing that nobody mentions... the throttle is PERFECT. I'm very particular about throttle free play, I like it as minimal as possible, and this throttle has 0 free play, which I love.
I don't understand why Suzuki didn't coat the rider footpegs black, like they did all other controls on this bike. I'm going to get them powder coated black once fall is here, they just look out of place. Perhaps aftermarket footpegs are an option, but I'd want a set with rubber on top to help dampen some of the vibrations like the stock ones do.
I actually really like the mirrors. Some reviewers complained about them, but I like the field of view and that they hardly vibrate. The fact that they fold is also awesome because I have a lot of toys in my garage and space is limited.
The seat... is ok. I may look for an aftermarket one at some point, it's a little too slick and flat for me, but still works ok. The leg position is pretty sporty, but not terribly so. I can stand flat-footed at red lights and my crotch is completely off of the bike, so that's a nice way to stretch.
I got right-angle valves installed when I installed new tires, which is a must for this bike in my opinion. I went with Dunlop Sportmax Roadsmart IV tires with a 55 aspect ratio rear and they have been really nice. Zero surprises on the road so far.
The windshield is ok. It doesn't really buffet my helmet, but it does throw the air right at my neck, so there is some exessive helmet noise. At least the air is clean and not turbulent. I'm going to look at some shorter shields as I would prefer the air on my chest in the summer, and maybe a longer one for the colder months.
So yeah... I'm happy with the bike, it was a good purchase.