Subjective question. Below is the mod on my list.
1. Sierra Glow; silica based paint protection (http://www.sierraglow.com/about/about.html)
2. Coil Mat; mentioned it at my previous post
3. Change the Kia Emblems (7 pcs); I got mine from Shark Racing
4. Change a more silent tyre; either Michelin Pilot Sport 3 or the new Goodyear F1
5. Getting Grounding cables, VS or Alternator Booster
6. Chrome door handle
7. Auto close side mirror relay kit
8. Front camera or sensor
9. Stabilizing bars; either import from Shark Racing or wait for Ultra Racing (not out yet

)
10. Some sound proofing materials to enhance the listening exp from Infinity sound system; STP
11. Change a lighter Crank Pulley
12. A lighter 18" rim; most likely Enkei as the default rim weigh around 10kg/each.
Edit: Forgot the most important one; TINTING. Got my one from Raytech. Very very nice. And looking forward for dual exhaust system but certainly not for now.
Bro, can share what deal you got from Raytech? Serdang HQ quote me RM2400 CS85 for all windows and V90 for windscreen.