Which car is more fun to drive?
This is silly. Go to the dealer, drive them both and decide for yourself. Someone is going to like the 430 more and someone’s going to like a 330 more.
Opinions are like buttholes…everyone has one. Only thing that matters is yours.
My opinion is that you get a Golf R.
Any tips on choosing a butthole?
It depends on your tastes. The new 330xi has newer tech and better engine dynamics and fuel economy than a 430xi. Conversely, you can probably get a 2019 440xi (which are usually loaded with many things that are just optional on the 2018 330xi) for the cost of a 2020 330xi. This changes the smiles per mile question. So, as recommended, you should consider long test drives with both series and make a subjective call that suits your tastes/needs.
I have a 2019 4 GC and 2018 3 series, so can’t speak about the 19/20 3 series since I only test drove it however I feel like the 4 GC is the best combo of the two, make sure to get the updated 350 dollar option for the digital instrument cluster makes a huge difference in the feel of the car being old/new on the 4 series.
Personally I like the 4 series more it’s the perfect combination of looks/ sportiness and practicality. Yes the head room suffers in the rear a bit but unless your carrying 5 passengers all the time or have someone over 6 ft tall at all times in the back seat it’s deffintley comfortable. Driving dynamics wise best bet would probably be a 440 GC with adaptive suspension. This is just my opinion I know many who like the 3 series more. The 4 also has a bit less visibility through the front dash while the 3 truly feels like a sedan. I absolutely hate how the new 3 series looks like from the rear feels like a Lexus to me.
Both are great cars and are fun to drive just depends on which you think looks better in your opinion.
Also consider the daily in/out in a coupe with heavier doors compared to sedan is different, as is just getting your briefcase in/out of the back seat. It was noticeable back when I went from my CiC to my 535.