Will I be able to hear my subwoofer?

I drive a 2011 ford fusion and i have just laying around a pioneer shallow mount 12 inch subwoofer that peaks @ 1000watts max. If I run a 1000watt amp will i be able to hear it in my trunk? Keep in mind my backseat does not fold down.

Advice on buying new mid-size sedan?

I'm in the process of looking for a new sedan. I'm considering new and used options, but I think I will go with a new one just because I drive a lot and I plan on owning my car until it stops working, or hits close to 200k miles.

Here are my options:
1.) 2018 Kia Optima SX
2.) 2018 Mazda 6 i Grand Touring
3.) 2018 Ford Fusion Titanium
4.) 2018 Ford Fusion Sport

What are the pros and cons of each, and ultimately which would be the best decision?

I want a reliable, powerful car.

If not new, I would consider those same options (beside the sport) in the year of 2016.

Thanks!

(My previous car was a 2012 Ford Fusion SE, which has never given me any major issues and was a pleasure to own.)

Is the Ford Fiesta (US) a good car?

I'm 19 and I'm looking to buy a new car next year as mine is very old. I don't drive a whole lot. My dad keeps telling me to get a Fiesta. He drove one and loved it. I like the hatchback version better. If it's a 2011-13, I'd get a SES, SEL, or Titanium. If it's a 2014-18, I'd get a well optioned SE or Titanium. I haven't heard too much bad about the 1.6L I4 engine. I have heard a lot of bad things about the PowerShift "automatic" transmission. I heard it is plagued with problems. So with that being the case, I'd get the 5-speed manual transmission. I do have a few questions about the Fiesta though.

-Is it as fuel efficient as said to be?
-Are owners happy with them?
-Does the stereo work OK? (can always upgrade later, I really don't care either way)
-Aside from the PowerShift transmissions, is it reliable?
-Is it easy to get in and out of?
-Is it comfortable?
-Does it handle well or poorly?
-Can a normal size adult sit in the back or is the backseat just for looks and kids?
-Can it hold up to being owned, driven, and maintained meticulously for 10+ years?
-Would it be worth it or should I just go with a Fusion or Taurus?

Added (1). We've had an Explorer for 13 years and it's been nothing but reliable but, I don't want an SUV.

Added (2). I'm considering the Fiesta due to the fact that 80%-90% of the time, it's only me in the car. Is the Fiesta safe?