Hi is been along time I'm away from this thread. Recently I did some updates on my persona and I just had my 30month service.
1. Ecu has a new update. I also had my transmission oil and filter changed. I felt the engine become slightly responsive. Before this I feel the car response like when drive a manual the clutch didn't fully release, the rpms goes up but not the speed. After the ecu update I felt the cvt is finally in the' right' gear feel.
Though these might be placebo.
2. Added sound proofing in the wheel arch. This could be the cheapest ever upgrade you can do to your car. My Cc6 is getting old (1 year), with noise being apparent. But with the sound proofing sticked in the inner part of wheel arch, the whole car just felt different. I only had mine done on the front, if you can afford definitely do both ends. The sound sheets cost around rm rm60 for 2m x1m.
3. A new head unit, I spent 600 for a new head unit but I think the best thing is to try it yourself at shops or even online review, don't ever trust recommendations. This is because some head units are suitable for your user style. Since I have stock, a cheap as China brand HU and now a Android HU, I would say speaker does the most effect. They are cheap, rm100 Sony comes in a pair + shipping.
4. Tint 2 mil nanofilm, shop owner say is up to 65% Irrr. My advise it do it good or forget it. I had 2 layers of tinit now, I still feel the heat, though the air cond does get cool faster. Get some reputables ones mine are cheap and the quality is expected.
5. Leather cover seat cover on top of fabric. This cost rm 258 buy from online. It is quite durable I have been using for 9 months. Is a massive heat sink, my ass gets burned everytime. Is worth it if you have good tint.
6. Custom sunshade. In short, get it. I got mine they range around 50 to 80. Good for those on budget and can't fork out rm2k just to buy some fancy plastic to stick on windows.