This is an informative post. As you know, I own the 1st batch 1.6MT Exec 2015 (no 2nd batch, already obsolete). I had all kind of noises in the interior in the beginning. When complain during service they asked to make an appointment which i did not have time to do so.
I solved all the rattling problem by myself and i can say it's almost 95% silent now. It has been good for about 6months. Below are all the things i did in order (major and minor). Some of these might be common to you guys
Major
1. Dashboard-Windshield (This produces annoying rattling because of the dashboard installation is not flush to the windscreen. Passenger side dashboard tends to have sponge coming out as well. Solution is to buy the rubber strip
http://www.lazada.com.my/16m-t-shape-car-s...0.0.e000PC&ff=12. Head unit krik krik sound. As posted in my previous post. This is caused by the head unit/ac vent panel (it's a single piece) rattling. Solution is remove the panel and use cloth tape those touching parts and joints (tape can be bought from aliexpress)
3. A/C knob and panel rattling. This produces krik krik sound. Removing the A/C panel not easy, it has 3 clips holding it, and i dropped 1 clip behind the dashboard while removing it. Luckily the missing clip does not make any sound and the panel can be fitted back without problem. Tape the rear of the panel joints with tape. The A/C knob is also loose, this can be pulled out by hand easily. Apply cloth tape to the surrounding area to make the knob tight.
4. A-pillar cover and panel near small window loose. I believe this is majority of iriz/persona issue that is famous and well known. Solution, just remove the cover, put some cloth tape and sumbat some sponge in the void area in the middle.
5. Door making faint vibrating sound. Can be heard when closing door and uneven road. Inside the door, both front passenger and driver have sound. They're caused by power window cable. Solution is to ziptie it to prevent it from vibrating freely.
6. Door making metallic knocking sound in driver door. Can be heard when closing door and uneven road. Loose lock mechanism have some play, you can feel the metal rod moving if you insert the keys and twist. Solution is to wedge some sponge.
7. Speedometer rattling. As posted in my previous post way back, use cloth tape.
8. Steering rattling noise. Caused by loose horn/airbag cover. Need to remove and apply cloth tape to make the cover fit snugly.
9. Small triangle vent above the A/C output at passenger side rattling. This is probably isolated issue only as the dashboard wasn't fitted flush, so got some play in the inside (Dashboard connecting to the vent). My solution is to remove the glovebox and wedge a rubber pad in between by inserting my hand inside it through glovebox area.
10. Spoiler rattle (1.6 Exec and Premium version). Remove the spoiler and apply cloth tape to the rubber part touching rear windscreen. Tighten it properly.
Minor - These are small annoyance, can be ignored but i try to do my best to kill it
1. Loose sun visor, this will make very faint rattling sound when you drive through uneven road. Solution is to make the sun visor latch area fatter to prevent play.
2. Rear 3rd brake cover loose, use a rubber/felt pad to wedge at the brake cover against the metal hatch body.
3. Glovebox hitting dashboard. Apply thick foam tape, can be bought from daiso.
4. Steering column cover. This produces knocking sound when driving through pothole. Solution is to open it up and apply sponge. I apply the butyl rubber (used to do door sound proofing) inside the cover to make it more solid.
5. There are some loose clips that holds the wires inside the door panel, not noticeable but i make the clip stays solid by wrapping with electrical tape and push back it in so in the future it won't get noisy.
Still unsolved
1. Rear rattling windscreen, sounds like something is hitting the windscreen but i couldn't identify the rootcause. Doesn't sound all the time, only 10% of the time when driving regardless smooth or rough roads. Sometimes rough road does not produce this rattling. Sometimes smooth road it makes loud noise like something hitting the glass.