Looking at getting a sc project cr-t end can for my 2019 bike it will have 2 inlet pipes from the cat, if i get a full system later on will i need a new end can with 1 inlet ?
As long as the outlets on the can match the OE headers you will be fine.
Quite a few people have fitted aftermarket headers to the OE dustbin so there is headers out there which are compatible with 2 outlet end cans.
If you're going for the stubby GP can be aware that it will be chavvy loud if you do decide to fit aftermarket headers at a later date.
I can't comment on SC project, but the similar, alternative Akrapovic stubby GP can on OE headers does sound very nice, so I'm sure thr SC Project will be similar.