LED bulb swaps for your internals, side lights and repeaters cost under £10.
Remove ‘u-bend’ plastic hose on intake side of air filter housing for more flow and throatier sound £Free or like I did source a small piece of aluminium pipe with a 30° bend for a more finished look £7. Sports air filters are snake oil on these cars so decent paper filters are just fine.
Sort out the wobbly ride with a set of sports springs £150-200 plus fitting.
Make sure you have decent tyres, and keep them inflated properly.
Keep on top of servicing. Always using quality filters/ oil (learn to do yourself if possible and save loads/ know what’s going in).
And treat it to premium fuel fairly regularly.
Decent first car, enjoy!