, Welcome to the GSX-S1000 forum! Nice to see your bike and hear the mods you've done and what you are considering next. You are considering a "throttle tamer" as your next modification, so I'm guessing your fueling is still a bit too 'abrupt' for your tastes. The throttle tamer will help. Before you buy it, ensure you've already tried to take all the slack out of your throttle cables except for 1mm to 2mm and try that. Sometimes there is just too much slop in the bike's throttle cables as it comes off the showroom floor. I'm guessing you already did this since you have done the TPS fix, too, but had to mention it. Throttle tamer is good but...
...getting your ECU flashed to make it fuel right would be even better. I don't know who in the Belgium area is any good, so hopefully some others will chime in.
As for the bike not being too confident inspiring at full lean, a lot of that comes down to two things:
1) The stock D204 Dunlop tires are really not that great. Not much grip and not confident inspiring. Replacing them with some Michelin Pilot Road 5s or Pirelli Diablo Rosso Corsa tires will make a tremendous difference. When buying new tires, get a 190/55
-ZR17 tire for the back (not the 50 profile tire the bike came with.) If you still have a lot of life left in those D204s, start running 36psi in the rear and 32psi up front. That will get more heat into the tires and make them a bit more supple, which can help until you replace them.
2) Replace the rear shock. Just about ANYTHING else will be a huge improvement. The factory shock is over-sprung and has too much high speed compression dampening, making the ride harsh and out of synch with what the front end is doing.
Hopefully you can get the bike to the point you love it and just want to ride all the time.