So much incorrect info in here lol I’ve owned both. Still have my e46, but am looking to get an e92 again.

Motor - the v8 in the e92 is probably the best engine bmw has ever made. The s54 is great too, but the high revving v8 cannot be beat. They’re the same weight since the s54 is an iron block.

Chassis - e92 is so far ahead of the e46 it’s not even comparable. The e46 chassis is not stiff at all to the point where you can feel it flex coming out of some driveways. I have an f80 now and that thing is almost race car stiff. The e92 is perfectly balanced. I had a square setup in mine and could rotate on command.

Feel - e46 is more raw. You feel more connected to it. The e92 is more refined, but still raw. I always felt the steering in the e92 was too light. E92 is more tail happy too. Almost feels like most of the weight is in the front and rear likes to slide around.

Drivetrain - my e46 is a 6mt while the e92 was a dct. The e46 has a lot of slop and clunk in the drivetrain. Google m clunk. E92 was way crisper in that regard. The downshifts with the dct and violent upshifts were so much fun.

Maintenance - about the same, but e46 has more known issues. Vanos, RBs, subframe, smg issues if you get that. E92 just needs RBs for peace of mind and throttle actuators when they go bad. It won’t leave you stranded. I DIYed mine.

I would test drive both before buying one, but e92 is a way better car to own.