You're about my age, and I am super happy to see that you're responsible with your money. You have more saved up than most people twice our age. I'm on a similar path as you with the money I'm able to make, save and spend.
On the other hand, I also believe that in life you shouldn't hold back on things that make you genuinely happy. And if that happiness, urge to own a dream car is to buy a GTI, then the hell with it. Go get a GTI.
Life is too short to withhold living your dream.
Have you considered leasing for a short term, 24/36 months maybe that's what you need, to get it out of your system, to taste the car, and get it over with.
I leased my dream car for 2 years, 2010 CC, I loved it for the time being, but got over it. Now I drive a Jetta TDI which is considerably cheaper to run. Saves me tons of money.
I'm gonna vote against financial wisdom on this one. Go get it.
Ideally tho, would be to invest the 25 grand, and collect dividends from it, which you could supplement with cash and pay as you go monthly.