I LOVE the sound for the 4-banger, sounds realistic and has a cool intake noise at high revs. It reminds me of my late dad's 1980s Honda Accord which was light, nimble and LOUD at speed. Thanks for bringing back the good memories :) Also your video is quite low res so I made a nicer sound demo for you: https://youtu.be/piLKJR2yYJM
Besides sounding like a V8, it's not a particularly bad sound.
It's not HQ as you say, but it still sounds pretty clean.
Some improvements are needed of course, to make it more "4 cylindery", halving the piston count basically :D