All of my hardy-ish sinningias go outside:
Sellovii and similar
macropoda
leucotricha
tubiflora
Bananas Foster
Arkansas Belle
Lovely
I let all of these except S. leucotricha go dormant in the winter. I grow in a gritty mix in clay azalea pots. I have to be super careful to let the cold nip the foliage, but not a real frost or I'll lose them.
