Alto K10 ICE advice please

Hi Guys ! This is my very first post in Team BHP. I am very excited to a part of this wonderful community. Eventhough I just became a member, a lot of info i have read from T BHP helped to make up my mind in purchasing my very first car, which I am happy to say is my new buddy, the Alto K10 VXi ( I will be writing my ownership review soon) . Let me start by thanking everybody. This post is regarding a small ICE upgrade for my car. Currently I am running a JBL X333 Head unit (JBL GT-X333) and in front I have JBL CS-4 (JBL - Product Support - CS-4) which is a 4" co-axial speaker . I wanted to add a little bit more bass to the existing support because I mostly listen to Metal & Rock and sometimes rap/techno. I couldn't feel the beats of the drum in metal / rock tracks and thereby loosing the feel of the music. I am not a fan of the Boom boom bass of the bass tubes so i ruled them off. Anyways, I thought of adding a ported sub (JBL Bass pro12 active sub) would be the best idea but being a complete noobie in car audio, I thought it would be better to ask for an expert help. So i went ahead for some consult with an accessories shop ( in Trivandrum, Kerala) talked to the shop owner( A really good guy and very polite and professional). I told him my requirements and he suggested that it would be better to add a 6x9 speakers in the rear (in boxes and not in tray as the weight of the speakers would bend the tray eventually) and if I still require more bass, I can add a SUB later. Only adding the sub in the rear and 4" co-axials in the front is an odd setup and the subwoofer would end up overpowering the setup and music will not sound good in my small hatchback as all the details from the front speakers would fade in the sub's low frequencies. Fellow T-BHPians, what are your expert advice to me on this ? please advice....please: (I never heard any ICE on any cars before other than my own so I have zero clue how it will sound ) The shop owner suggested a pair of MTX T6C693 - THUNDER6000 series (MTX Europe - T6C693) which is a 6x9 speaker for 6k. Specs RMS Power : 120W Max Power : 480W Impedance : 4Ohm Frequency response : 27Hz - 25kHz Sensitivity : 94,0dB/2,83V/1m Diameter : 15x23cm (6"x 9'') Mounting depth : 76,5mm As per the owner the MTX T6C693 would give much better bass than any of the other 6x9s and would probably eliminate the need for sub. He also suggested two add a two channel JBL GT X424 amplifier(JBL GT-X424) as the 6x9s will sound much better than connecting directly to the HU. He also suggested damping (Brand: Dynamate) in the rear hatch door and two rear doors. Front doors are not required as per the shop owner because there is no speakers in the front door. These bring me to my questions 1 ) Is the second setup (MTX 6x9 and JBL amp) would sound good ? I mean JBL GT X424 is an amp that has only 50W RMS per channel but the 6x9s have 120W RMS. If I am going ahead with this setup, am I underpowering the speakers with the JBL amp ? Will I be able to extract the full potential of the MTX 6x9s with this amp? Should I choose another amp? If so please suggest me a good amp which would be able to drive the speakers to full potential and safely too. I appologise for the lengthy post. I am a total noobie and has zero experience in car audio. PS : Also my friend suggested a good component upgrade in the front doors as it would improve quality but I really do not like the idea of cutting a hole in the car . So currently I am not considering a front component upgrade atleast not in the door. I am looking forward for your valuable suggestions. Thanks in advance.

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