Just take it off and ride around with it off for a few days. Get the unpainted plugs from Home Depot, will only cost you $2 and then if you like it spend the bucks to get the painted ones or to get the holes sealed. It looks great without the spoiler. I converted a few people to go spoilerless after they saw my car in person. Pictures do not do it justice.
My opinion....keep the spoiler. I am not fan of the spoiler-less look. I wonder if anyone would change their tune if the GTO came without a spoiler and start putting spoilers on. I think the only thing that the smooth trunk look has going for it is that it is different, not necessarily better. I mean, it looks good, and I would have no complaint if that is how they came from the factory, just think the spoiler looks better.
I respect whoever does tha whole spoiler delete thing, but unless u get a different spoiler like just something small...I think jhp has a nice style to keep it sporty, but to me without the spoiler it looks like just a sedan trying to be sporty...i personally think the spoiler ads a lot of style
remember this, if you decide to remove your spoiler. Make sure to check and see if the fine boys that work for GM over tighten the bolts to the spoiler first and see if you have any crease marks. I love the spoilerless look but I forgot to check for creases on mine and when I took it off, I had 4 deep creases. The Top Shelf plugs won't cover the hole up either.