Just curious, seen any 2000W RMS Amp before? Very curious how it will sound and what the rated Peak will be... mmm 10,000Watt and also brigeable to reach what level at what Ohm....???? really curious.... Think can really kill speaker that not measure up....
Howie got the panel for me.. more expensive than Aiman but he gave me his personal guarantee that its up to his "standard" ...
I also dont do up the A Pillar... just use a silver cup for the tweeter... designed by EA again... half way hanging... look like Turbo-boost... hahahaha....

2 biji 2000wrms kicking mid in our type of ride... think SPL level will be really bad for our ears..... add 2 more for sub use... think kaca also pecah...... Dont know the car alternator/battery can generate enough power to run 4 biji 2000wrms....
For your tweeter think need bowl.. can see if Oldtown willing to sell you a set to put your tweet.....

A better HU give you better option later when you upgrade ICE. More processing power and more output. ICE is a journey and its better to have an idea your future plan. Or else you be limited with your choice or need to spent more money on things that you could have done earlier (learning curve problem).
Lastly go to a installer that have done your model of car before, ask them if they done before as each car have their own set of complications. Your GX can look up EA or Audiocreation. They done before....

ICE do have it limitation. There is only so much that we can do within a budget and constraint of a vehicle interior. For those of us who are Headphile or Audiophile, we do have another set of standard of sound reproduction that would defer from ICEer.
Those of us with Speaker setup would compare with positioning, floorstand with multiple driver size, multiple subwoofer, ported sealed and also room correction. We expect the stereo sound to fill the entire room and also have a sweetspot. In addition to this, the luxury of minimal environmental noise and cleaning up the main noise. Not forgetting some who even regenerate power for audio reproduction purposes. If do have a chance, do try to listen a good Stereo Setup or maybe visit the annual KLIAV to get a taste of this side of the poison.
Unfortunately we cannot wear a Headphone while driving. We need to share the sound with the other occupant as well in the vehicle. If can, I would just spend on a portable Hi-end Headphile gear that could cost the same as a ICE setup. Think of a mid end Headphone with noise cancellation, media player, portable DAC/amp that can be just linked to the 12v power adaptor. Put one Headphile gear in a car and try compare it against decent ICE. Think where your preference be.
Therefore rear speaker do help in imaging as we cannot control reflection point in vehicle that easily. Cannot simply have egg tray stuck on window.
Anyway, it's still individual preference. If you want to stick to ICE principal of front stage without rear speaker then its your call. There is still some of us who do dream of having certain difference in our setup. Also there is those some of us who try to reproduce something that near to impossible but what the heck, nice to daydream. For me I want the sound of a Denon D7000 powered by a full wadia setup sound in my ICE...... Daydreaming....

Think Izso was trying to make a point that rear fill is a personal preference against an argument that its a waste of money. In some case rear speaker are needed as not everyone drive a compact 4 door car. There are some with Welfire or Madza 5 and think rear speaker would be needed.
In certain cases, adding more speaker would improve the audio quality, that why we have 3 way, 4 way front stage. All depend on how it's been done. Look at those Floorstand speaker in HiFi with multiple drivers. ICEer trying to recreate the same with different size driver and positioning.
Therefore some of us which decided to remain 2 way, would maybe rely on the rear field speaker to help fill the null and void. Who do not want a front stage with .75" tweeter + 1.5" bigger tweeter + 3"mid + 6.5" mid bass + 8" bass running off xover with multiple amp with dual 15" sub on monoblock plus a 6.5" running off the HU as rear fill for the fun of it?
As mentioned, ICE have limitation and we need to work with those limitation. Also, competition setup are to cater for competition needs while a day to day vehicle should suit its owner fancy.
Therefore I believe a vehicle with sound coming from everywhere would suit a fella who like clubbing as that what it is like in a club while a concert goer would think he had gone into a audio nightmare.
Finally a vehicle is not like a listening room where you can use bass trap, acoustic foam and room correction treatment. Reflection is controllable only to certain extent and then it's up to you how much you can tolerate.
Finally, everyone ears are different and expectation are also different so don't expect your installer will understand what you are trying to achieve. Therefore compromise need to be made unless you can manage the ICE installation all by yourself.......

The 4x50W are Peak power rating per channel. The Home AMP of 60W, 100W are RMS rating. So need to find out the RMS power so different model different RMS and also different sounding due to different DAC and BIT Processing.

Then upgrade those "not entirely true" item to the next brand upward... but think not easy to get also as your "brand" already so $$$$$ one...