If yours is a Myvi 1.3, then the Myvi 1.5 disc + caliper is pnp and is quite a decent upgrade. If yours is a 1.5 then you'll need to dish out some cash to custom make the bracket to hold any other caliper in place. Wira one, Honda one, etc. 4-pot in a Myvi is overkill and you'll need way bigger rims.