You can actually turn them off, but to be honest, those effects aren't even that "flashy". You won't even notice them most of the time.
What's nice about Unbound is that it's actually quite different when compared to the previous titles, at least when it comes to car mechanics, racing, and customizations. The online mode is what makes it fun. The mods are quite advanced, and there are tons of ways to make a car go fast. It's not just different classes of parts; weight comes into play, which helps with cornering, and different car builds for different tracks and tiers.
I've played Need For Speed all my life, starting with the first title back in the 90s. NFS 2 I've played the most, it was just something else. And compared to all the latest titles in the past decade or so, Unbound actually feels a bit "different"; in a good way of course,