Recently bought myself another one of these after owning one previously for 2 years then selling it. Great cars. My first one was stage 1 tuned with a charge pipe and boost pipe upgrade, m performance exhaust. Current one has VRSF downpipes and charge pipe but standard exhaust and no tune.
First 'mod' to do is definitely charge pipe. Then coils and plugs if you need it. Depending on kms, waterpump and thermostat might be due soon and intercooler would be a nice upgrade if planning to stage 1 or 2 tune it in the future.
Regarding brands, plenty of options out there. Invest in some good tyres to somewhat mitigate the lack of LSD since these cars can break traction quite easily with the low torque power.
Most important thing to do on these cars is oil change, oil change and oil change. Never go past 10,000kms per interval and always use good quality fully synthetic 5w-30 or 5w-40 oil and a good filter.
Otherwise, brilliant cars and will surely put a smile on your face.