Hey Frank-
This has been discussed before and yes, the spoiler does add too much weight for the springs to auto-open the trunk.
That said... some of us (me included) have added a few zip ties to help compress the springs and make them a tad stronger so they will indeed lift the trunk and spoiler.
There are 2 standard notches behind the carpet trim for setting the tension- possibly 1 setting for trunk stays closed (without a spoiler), and 1 setting for trunk opens (still without a spoiler).
If your springs aren't already in the furthest rear position just use a pair of pliers to make sure the springs are hooked to the furthest rearward notches to provide the most tension. Get a good grip, don't let go.
Then I added 3 ties to only my left side and it has been working fine for about a year now. I originally thought I'd add more to the other side so the trunk wasn't being pulled harder from one side than the other but it has been totally fine on my car with zero signs of twisting, I'm too lazy to add them to the other side at this point.
Here's a link to the discussion. Kudos to InfiniteImp for figuring this out. In Post #11 he shows trying the spring hanging out past the rear of bracket housing, I didn't find that necessary, I just used the furthest rearward notch.
I show off the finished product with a video at post #27. Have fun!