May be, its due to 5w-30 semi synthetic by Suzuki. If you'll use 5w-30 fully synthetic by Total, then you might feel some difference.
As you have said that you drive the car to its full potential, prefer 10w-30 / 10w-40, instead of 5w-30 / 5w-40.
In your particular case, it won't bring any harm. Still, now I am convinced and of the opinion that engine flushes are unnecessary and may not be used, unless / until they are absolutely necessary (which does not seem in your particular case).
I hope, all above helps and guides. Thank you.