What's the cause of the weight difference between the '05s and the 03/04s?

Thanks.

I believe about 100lbs

I wish our cars weighed 3000lbs
Then we would probably be able to keep up with the M3s

They would.

I think its all the new "googies" they added on.

Those 19's aren't exactly light. They claim to be forged but that still doesn't mean lightweight.

they actually are pretty light for 19s buddy. if you knew who made them, u wouldnt have said that.

VOLK! The 19's are actually VOLKs... >.> ... or should be...?

They are probably Rays just like on the track Z just a diff design.

Well, someone said they say "VOLK" on the inside (the side touching the rubber)... but I haven't had the time to check myself.

It says RAYS on the inside, not Volks. Volks are made by Rays so same difference, especially when the stock 19" are monoblock fine forged wheels. As far as weight~ The 19" wheels definitely weight less than stock 18". - I have weighted them both on the same scale.

One of the heavier items I can think of is the power motors from the front seatbacks.

OEM 19" are lighter than OEM 18"...
but i dont know about the other things...

My guess would be that they added more sound deadening materials. It could also have something to do with the variable exhaust valve timing change that they've implemented. Could also possibly be due to having heavier brakes (no more Brembos).

Could be a number of things.

I would say it could be the suspension, rotors, and everything else everyone just mentioned. But as I said before...who knows how much both models weigh until you weigh them yourselves. Too many variables to factor in, I say if it looks the same, drives the same, it's close enough Slight differences here and there, but the ride quality is still the same to me.

8 ways power front seat vs 4 ways power front seat
power tilting and telescoping steering vs manual tilting steering.

With those extra motors in place, there should be more weight involved.

Sorry there buddy, I guess if you knew who made them, you would have shared that with all of us buddy. I guess the 19 inch tires are lighter as well then huh? Lighter rims don't mean lighter assemblies there buddy.