Which BMW and BMW M cars have you owned to come to that conclusion?
Oh you have to own something to know the differences?
For the record, I haven’t owned an M car, but many family members have.
Hence, I would say I have had more experience than most in:
E46
328i
330i
M3
E92
330i
M3
F3X
340i
M4
(I own a 320d and so I’m most familiar with the F30 platform)
F10
535d
M5 Competition
All of which have been owned by 2 different people, so they’ve got a reasonable amount of experience moving from a top of the range petrol (diesel in the case of the F10) to an M.
Completely different suspension components and engine iirc? As well as lots of other bits fiddled with.
It’s relative. Yes, an F80 M3 has a completely different engine, but it’s still a 3L I6 with more horsepower than you need on the public road.
Just because something is different, though, it doesn’t mean you’ll notice it.
As I’ve mentioned, some of you will be able to notice the (at times) acute differences between cars.
But when we’re talking about two BMWs, an older M3 vs the newer G20 M40i, these differences, for most, will be subtle and mostly emotional - I.e. how does the car make you feel (through sound, suspension, steering).
The difference between an E92 335i and M3 was considerably more, given the completely difference engines.
Again, I’m not saying there isn’t a difference, but between the two cars in question, it’s likely minimal for the OP, unless they’re specifically looking for the greater emotional connection a proper M car will provide.