Spoilers and Allowable Stickers?

Howdy Y'all!

I finally found a custom bumper sticker I really want to put on my Get 2 Prius, which is prompting a 2-part question.

The first question is, is it legal (in Colorado, specifically) to put a clear sticker with words on that lower, back window of a Gen 2 Prius? While I don't really use it to look out of and while the wiper is onlly on the upper window, something tells me some cop will say it is 'obstructing my view' and 'must be removed.'

The window is not the ideal place for my sticker, as it slopes inward toward the top and is shaded by the spoiler, leading to a second set of questions.

1.) Are there different spoilers with a greater amoung of vertical surface space I could replace the current spoiler with, so I can put a sticker on it?

- and -

2.) Can the spoiler simply be removed, without making the car look weird (as a car with a missing bumper does, not style-wise) if it IS legal to put a sticker on that window?

I worry in this case, I would need to modify the text width to allow it to still be readable (ala Star Wars style, where the words are wider at the top, so they appear equal in size to the reader).

I am sorry to ask such a strange question on this forum, this is a very important sticker to me and I want it to be visible. The bumper is just too darn low, I would put it on the back of a trunk, in a different car.

The sticker dimensions are to be five inches high, by 12 inches wide with colored letters, outlined in black on a clear bumper sticker. The lower back window has a slight tint to it.

I would appreciate any advice, it may seem like not a big deal, but because of this sticker, to me, it is.

Hugs and hearts!