Long time Prius Driver, finally one of my own

Greetings, ive been lurking on here for awhile and decided it was time to start posting/ getting some answers to some of my questions.

in 2001 my mom bought a prius. I was 10 and had no idea what a hybrid was, only that her car got about 50mpg.

I learned how to drive in this car, when we inherited a 2004 prius from my grandfather I hoped to be given the 2001 as my first car, but my mom refused to drive the newer model.

She doesn't like the hatchback body, or the touchscreen climate controls. compared to her car, the '04 is pretty loaded, she isn't the most tech-savvy person so I guess the car just confused her too much.

My dad hated driving this car too, he said it hurt his back. He liked how it got more than double the mileage of our other car (2001 Sienna). Also being a hybrid he could park on the bottom floor of the garage.

My dad recently bought a new 3rd gen prius, so I'm now the sole operator of the 2004.

About My Car:
2004 (Baby Blue) With Nav, Bluetooth, HIDS, In-dash cd changer
85K miles (young) we got the car from my grandparents in '08 with 40K

So I guess we are a family that drives prius, prii?

Now for the questions
at 85K what should I replace/ will I need to get replaced soon?
Is it bad to change to synthetic oil? My next oil change is in 250miles

I live in Mass. we get alot of snow, this car sucks in snow. Will chains work to get me out of a quick jam or will the mess up the traction battery somehow?

I know- I know, I should buy snow-tires, but they are expensive and im a 19yr old kid. My parents (both doctors) insist that the oem all-seasons they use on their cars are fine yr round, however they commute 50 miles each way on the highway. I do alot of driving around town/ take the backroads which are usually less well cleared.

My tires have >75% tread, one is brand new because my dad got a flat.

Since we have owned this car, the driver's door has made an awful screeching sound every time you open/ close it. (passenger's opens normally) it looks to me like the car had a minor accident near the drivers door hinge.

Will this get worse overtime? Should I get this fixed?

(When we got the car the rear-right taillight was also cracked and the back right fender is still sticking out a tiny bit.)

Mods Im gonna do
1. Remove trim rings (I hit a curb or something and one popped off, drove around with 3 but i took them all off the other day when I realized how easy they were to take off) Wonder why toyota put them on at all, looks better without.
2. Paint Wheels Black OR Polish Wheels. Anyone polished the stock wheels?
3. Tint. I miss the stock tint in the sienna. I want to do 35%. Prius is a greenhouse..also will make the car look alot better imho
4. Tinted Tails: still debatting doing this, but would match rims/ tint that I plan on getting
5. Suspension/ Handling Upgrades:
Ive heard about the chassis brace, definitely gonna do that one soon.

Which of these will have the best bang for the buck?
Strut Tower Brace
Front and Rear Sway Bars: TRD Corolla, Matrix etc.
New Shocks/ Struts...no brainer if I need to replace those soon, otherwise I want to lower the car a bit

7. Audio Upgrade. What speaker locations are drop in and replace with the JBL system? I work at Bestbuy so I get a good discount on the speakers and installation. I want to get a decent set of components and a small sub (still debating where to put it)

8. L.E.D. Lights
interior bulbs, maybe footwell lighting

other ideas, led headlight strip (audi) style

 

cool, definitely gonna see if I can replace the tail lights with leds, one of them already failed.

I think my next "upgrade" is gonna be to order a new transponder, I accidentaly reset the SKS and locked my key in the car. We can only find the one key and I was parked in the driveway blocking both my parents. Luckily AAA came and unlocked the car...took them about 5 minutes