I love my ‘15 428i (just hit 60k miles), had since ‘18, almost fully optioned (except no Xdrive). It’s awesome, I love it, but after having driven a new M440i loaner, the 28/30 is just not worth the money saved vs a 35/40. Also there will be some repairs because of 4 cylinder you might not have in the 6. Namely I just had to replace right engine strut. I know there’s more stuff that comes with the 28’s.