[S50Sinner]

As MikeFocke said, you'll want to upgrade oiling if you go to R-comps. If you're not in a position to do so, stay on street tires for now.

I'd focus on the most common track reliability mods so you can maximize seat time:

1. UD pulley so you don't cook your power steering fluid

2. Upgraded oil system. There are a million threads about it, search terms like "deep sump", "ultimate integrated dry sump", "accusump" and "oil cooling upgrades" for solutions, and "oil pressure on track" or "oil cavitation" for broader discussions about the issue.

Once you're confident that your car is going to survive the process of going fast, I'd start your upgrades based on what you feel it's lacking. At this level and budget, it's all about adjusting it to improve your consistency, that's how you get fast. I'd consider

1. Brake pads/fluid if you're experiencing brake fade

2. Camber plates or adjustable LCAs if you're still feeling excessive oversteer after getting a track alignment

3. A more secure bucket seat if you feel like you have to keep yourself in place (whether by the steering wheel, dead pedal, knee on the dashboard, whatever)

4. Some clutch pedal adjustments (helper spring delete, adding a small bump-stop block behind the pedal) if you feel like clutch action is slowing your shifts

5. Upgraded shift cables and linkage if you feel like you're missing shifts

6. Sway bars, if you feel like the car is soft/wobbly in corners

All of these are on an if-needed basis, but brakes are a maintenance item, so even if you haven't needed them yet, upgrade them when it's time for replacement.