It looks fine but only when it's tucked in a bit. It's a 3" pipe so is the right size to look decent, it just pokes out a lot.
A cousin of mine has a 530i Sport and his pipe was cut so the end fits flush with the valance, looks much better. Any decent garage should be able to cut yours for next to no money. Your pipe does look like it hangs a few cm lower from the tip of the valance than his though, I don't know if he managed to raise his somehow.
To get twin exits you'd have to get one custom made and request more baffles. I do believe Peco should be able to do you one (fully stainless steel) to your spec, might be worth giving them a ring?