Compare in terms of? Just test drive both and try it out to see which one you like.
I've tested both before I chosen M3.

not sure if the Kruk Kruk is the same, my GVC got the sound of something loose from the front when going thru uneven surface, most obvious when turning up car park with rough surface.

acceleration at low gear will hear engine knocking "kla la la" sound.
turning steering to the right till the end while parking will hear a 'dok' sound when car move.

the engine also got an aeroplane sound which mazda sc told me is normal, on aircon got gas release sound which mazda sc also told me it's normal.

I wonder how does it compares to stock Toyo and PS4..

arm bush, brake calliper, steering, dashboard are things that will produce noise over time.
if you have such issue, SC will need at least 6 hours (service + fixing) to solve it (maybe permanent, maybe temporary)..

Sure is zero benefit? Skyactiv is high compression engine.
I'm not expert but I read some article and research, high compression better use highet Ron, not true?

I tested before buying it at Mazda event. With Honda Civic to compare some more. When I made the s turn with Civic my friend sit at the rear got his head bang to the window, but the same didn't happen to Mazda 3, that's why I've chosen Mazda 3.

Mazda 3 doesn't have lane keep assist, it's merely lane departure warning. I turn it off at town driving, only on sometimes on long distance drive.