Your really putting too much thought into this
Scratch question #1...if you're worried about mpg then don't get an SS.
#2 it's just like any other car. Just don't slam the gas and you'll be fine. Slam the gas and you'll lose traction. (probably something you've never experienced since the golf probably couldn't even spin it's tired on ice
#3 you're issues there are all rare. I wouldn't worry about them. Except paint...but like you said you shouldn't be concerned.
#4...I am 22...father cosigned...I got a 4.45% interest rate. If you can't get 7% or lower then don't buy the car. Keep walking out until the dealer gets you under 7% nomatter what they say.
Idk how well you know how dealerships and banks do interest though....if the dealership can get you to sign on a high interest...the bank will give them some of the money back. When I bought my v6 I agreed to 16% interest
. Then I found this SS which was at a Toyota dealership that my friend was a salesman at. He told me all about interest. The dealer can always get you a much much much much lower interest than their first offer. But they trick you by blaming the bank saying stuff like "this is the only bank who will accept your credit" "this is the best this bank can do" so they can put the blame on the bank and not themselves. Making you think "well this is the best rate I can get". When they are straight up lying to your face. Keep that in mind
. Put down the whole 10 grand as a down payment. Or make a bad decision (like I would do) and put 3 grand down and 7 grand into a supercharger
You need a cosigner also.