The type 03 was originally studied by the JMSDF but eventually selected the ESSM but now JMSDF is having second thoughts since ESSM only has semi-active terminal guidance limiting the number of missiles they can launch at one time.
The type 03 is equipped with a fully active terminal seeker so it does not need terminal guidance from the ship making it more useful under saturated attack.
By the way the the variant of the type 03 SAM for the JASDF is the AAM-4 AKA type 99 AAM.
As for width, the maximum canister width for Mk41 is 71 cm so it can fit a quad pack type 03.
For size quite sure 1 cell of Mk 41 do 63 cm but for Mk 57 do 71 cm... maybe the confusion in more
very difficult to have the size of the cell itself in fact canister max size.
I have search several times and i know the difficulty...
But only project ... I thought you were saying that the missile for a ship existed a big difference.XRIM-4 - Naval variant, project was previously canceled but effectively resurrected in 2016