Almost certainly to be worn with shirt and tie. I can't fathom wearing a coat without a shirt, and I can't fathom wearing a shirt with a coat, without a tie. LOL.
But, what about 34581 as trousers, and 34537 as a coat? Or is it preferable to do a two-piece donegal 'suit'. Not smth I've done with smth with prominent colours like this.