yes, this is the best way to know whether something suit u or not...but in some case, test unit are not available and it's not all shop will let u test....so at this situation recommendation by experience is very important.

Sorry, not Melaka guy.

You can try GM Concept or Focal Performance(If I get the name correctly).

Most of the speakers will perform better with amplifiers, because it amplifies also because your HU not kuat enough to amplify.

If you are new to ICE, I would tell you to install step by step, instead of putting everything in together.
Both ways will definitely show some improvement, the difference would be you will know what are being improved.

If you are new into ICE, go and listen to it yourself will be easier for you to make a decision. Instead of reading what people is saying in the forum.

But I can honestly tell you, any shop that is really into making business, "Test"/"Try" and listen is something that they will not hesitate to do for the customer.

Melaka definitely have a proper audio shop, since you have a Almera, just drive around and lookout lor...

sometimes i have go to melaka. Maybe u can pm me ur number, so next time i go to melaka can let u try to listen to my car lo