what do you mean by trim the backing plate
There's a "dirt" shield behind the rotor, it's meant to keep dirt/rocks out, but it really holds it in

I think most just remove it completely. If you're looking for calipers within canada, I had a hard time finding someone that still has them available, I went with used.... I haven't done the swap yet, I'm going to on my new kick

I also found that only the 96-98 4-doors had the vented rotors, but people in the US said all year 4-doors had them.... Canada must be different?