Wait till later you will be happy you did this mod.
In the picture shown only 4 ribs have been modified not all ribs.
Looks like all of the seat ribs have been opened up to me... and Yes the mod for removable sections on the center 4 ribs is well documented.
Yup... if you read the first post, Daniel even admits to opening ALL of the ribs, I think some are looking at the "rib mod" to the four inboards... that's not what he is talking about. If you look at the stamped area, you'll see the ribs have been trimmed back in this area.
I would say it's time to order 4 new ribs...
You are probably right. I sent Vans an email to see what they say about it. I will update the thread with their response incase someone ever makes this same mistake.