Man........you are living in driver's heaven.
What you want depends on your budget. You have to separate your wants and needs. My 2 cents for where you are at and doing.
Good tires. Michelin Pilot Sport 4S. Great summer tire. Don't know if you are going to run in cold weather or not. Winter tires. Don't ask me.
Brake pads and fluid. Pads, I ran the EBC YellowStuff pads for a couple of years. Good pads, but do dust more then the oem. Others run the Hawk and Mu pads. Brake fluid. Bleed your brakes and use something like Motul 660 or better. If you have a stick. Bleed the system and use the Motul 660 or better fluid. Also wrap insulation around the clutch line hose near the exhaust pipe. This will help to keep the fluid from boiling.
Don't know what your oil temps are. But an oil cooler will keep the temps down. The ECU will start to pull timing when the temps get around 240F and then go into limp mode around 280F until the temps come back down. Fast Intentions and Z1 both make a good kit. If you decide to install one and drive in temps below 50F. Make a cover to go over the cooler.
The above will give you a lot. To go beyond. Germany has some goofy inspection laws. So check them out before doing anything else. The stuff you want to put on next has to be TUV appoved or something like that.