We have been out in gusts to 45. We certainly did not go that fast, however.
The Wave performs great with winds in the 20s and loves it. You have to hike aft with you legs under the tiller in order to keep the leeward bow from digging in.
Personally, I would take the backrests off and throw them away -- you need to be able to hike the boat.
And the jib is pretty worthless as well, since you cannot get any luff tension.
Rick