Will my car need a new head unit and speakers?

My sister gave me her PPI 600 watt amp. It has 6 channels (not exactly sure what this means). I also received a sub that is a 12" Kicker in a box. I drive a 2007 Honda Civic Hybrid with a stock touch screen navigation system. I have no idea how wiring a new sound system works. Will I need a new head unit? I don't think I can do that because there's a nav system. Will I need new speakers to accompany this new power? Pretty sure the speakers I have right now are super weak. How much would new speakers cost? I'm so lost. I appreciate any help! Thank you.

Added (1). I'd also like to add that I would have this sound system installed somewhere. I would not do it myself. I'm just wondering what I'm dealing with here.

Does the 2016 Honda civic have an aux input(3.5mm jack)?

Because I have seen its features and there doesn't seem to be any. Is there another way to connect and play music using my phone? And please do not tell me to buy some new kind of cord or make me set up any of that complicated android auto or Honda link system or whatever.

Advice on buying a used car?

First off, I'm 18, looking for my first vehicle. I don't have much help in this process so I'm looking for whatever advice I can get. I've had my eye on a used 2012 Honda Civic for awhile. 45,334 miles. It was originally 12,795 but they recently lowered the price to 11,997 because "it's been in inventory for awhile and has fallen through the cracks"… I set a date for today with a salesman to look at the car. I went in test drove it and tried haggling the guy a little. (Thanks to google for teaching me how haha) I let him know I've been looking at other vehicles and weighing my options. In conclusion I made an offer of 10,500 for an out the door price. They counter offered 10,997 before finances. Asked if they could at least do 10,500 before finances and it was a no. Let him know I would think about it, talk to my dad and I d be back Monday. (In two days) my hopes is that when I don't show up Monday they ll contact me and hopefully make another offer. Is there something I should ve done different or should do?

Good subwoofers for 2002 Honda Civic?

I'm looking into buying subwoofers for my Honda Civic and honestly i'm lost. I need a good brand and all the other essentials. Like a good size woofer a good size case to put it all that stuff. And maybe a good radio head.

Is It a good Idea to lower the suspension of my car?

I'm thinking of lowering the suspension of my 2005 Honda Civic Ex Special Edition. Only reason why, is because I really dislike how the car is kinda sitting a bit too high for my liking. I want it shorter, but i feel like it'll be too low and would be scraping against the ground or if I tried to go over a bump or something… It would **** my car up… Which idea is best? Lower the car? Or just keep it the way it is?

How true is it that you should avoid 1st year cars due to unknown problems?

I have always heard that you should avoid the first year cars (new model or major redesign) because they have the most problems. Is this true or a wive's tale?

I was thinking about buying the 2016 Honda Civic, which underwent a major redesign, but I'm glad I didn't because they forgot to install some bolt in the engine which causes fires.

Nearly crashed, what should I have done?

Okay so I was going down a road and this 2012 silver Honda Civic got really close to me and was tailgating me. I didn't say anything to the person in the passenger seat because then they would say, "You can't control what happens behind you, you can only control what happens in front of you." So then we started going to a light and it was turning yellow and we were far from the light. He starts honking at me many times. The light was solid red and I was making a right at the light. All of a sudden he went on the opposite side of the road (solid yellow line) and speeds RIGHT THROUGH THE LIGHT! Everyone was just sitting there watching him and I was really scared. I then made a right because there was no "No Turn On Red" sign. Then the person on the left of me started coming but he/she probably knew how scared I was so she started slowing down as I went right. He/She was far away though. If there was an accident with the Honda Civic, who would be at fault? Me for not getting out of the way or him for speeding and crossing a solid line at a red stop light and going through it or someone else that started going at the green light. I kind of know the answer but I just want to make sure.

Should I switch to a BMW?

I'm currently in 2nd year of medical school in California, my last 2 coming years of medical school involve rotations at hospitals and some campus time. I worked and saved up 72k in the last 6 years and am currently driving a 2012 Honda Civic.
I'm thinking of trading it in for a BMW X1 or BMW M235i, both cost around 50k. Is this a good idea? I do get a warranty of 4 years/50k miles, the BMW Ultimate Service no cost and I will probably drive it daily.

Why does my Civic 5spd clunk from reverse?

I have a 2001 Honda Civic 5 speed 1.7L and when I back up and let off the clutch there's a pop/clunk sound from the front end. It seems to only do it after pushing in the clutch and releasing power after reverse. I can't find anything obviously loose, is it the CV, tranny, or something else?