well, kinda obvious the noise is from there as you can hear the plastic noise, however your suggestion sounds worth to consider. Too bad it's intermittent and it always pop up when i din expect it to, that cause a lot of time for me.. Damn.

If it is one pair, then others no need to sell already, confirm that is the best deal for the century. So of course logically it is the price of one single uno biji 

My bro alza with 6 adults went pass a bump, slow but still kena the undercarriage. His is the standard model without skirting.

this happens when the bump is too tall and you goign too fast with full load. i forgot the max load you can put into the alza (should have in the owners manual) but one thing i can guarantee is the suspensions getting "soft" when it's full load as the springs & absorbers are compressed. It behaves like my 1st batch myvi when it's fully loaded especially during cornering.

totally agree!

Hmmm... looks like either the bump is too high. i'm not sure any bars will help to improve as the suspension is cater for the load fluctuation in the range of 420kgs (assuming 70kg per pax, from 1 pax to full load exclude cargo), that's a 36% of the vehicle kerb weight. Unless P2 is really into the suspension like Proton did (i doubt that because P2 ride and handling are always sub par compared to Proton), else you don't have a fine tuned suspension from P2.

Maybe you gotta make some sacrifices, if your car always fully loaded, get a harder suspension. If it is always single driver, opt for softer ones. Coz usually you can't get best of both world.

i personally skeptical on spring buffer (maybe i buy cheap ones), the feeling is nice for the first few days, but after that, the suspension became soft again.

no...! 

i pakai 1.5l hatchback, already feeling more juice than a 1.5l heavy-assed Alza... Alza should be around 1.8l for achieve a balanced power-weight ratio...

i personally feels that alza accelerates better than almera (tested both before buying alza). The crucial criteria of acceleration is not always about the max torque or max horse as you seldomly push the engine to that extent to squeeze out the power needed. Alza engine is tune to the extent that the torque is ample in the range of 2-3k rpm which makes it nimble during city drive. Am driving 2014 FL alza, so far satisfy about the noise, anyway don't expect much from local car insulation.

i remember there's a concept car show case by daihatsu back in indon last year on the upcoming boon luminas replacement. Until that concept bring to production, alza will still be stay for some time being. in fact i don't think there's any new innovation they able to bring in for alza replacement except giving it an aluminum block without vvt (toyota etios engine), coz so far there's no toyota / daihatsu 1.5L engine that comes with aluminum & dual vvt. Or they wanna bump up the engine replacement and get a toyota 2ZR engine with dual vvt (call it a day dreaming). 
let me guess, you kinda always trapped in traffic jam? as the battery is direct hit from aircond cooling fan, it dies easily especially you are crawling in traffic jam.