The larger spoiler comes only as part of the exterior pack. To be honest I don't think it'd look right without the rest of the pack (particularly the 'dip middle' verion for the sportback). Congrats on your order!
To be clear though, I definitely would get the exterior pack - I think it's so worth it to make it not just like an A1. I think the 18" wheels are nice (they get a lot of compliments) and the red details are also a great touch.