I evidently have the only H20 Magnum in the country
It's 14 years old now (5 yrs on the wings), and holding up well. The biggest issue I think is that you walk on top of the decks a lot more (getting up and down from the wings); I have had some issues with delamination. We sometimes single-hand off the wings, but other than an occassional kid wanting to trap, just don't go out too often. The whole point of the wings was to get righting moment without having to work
It's not a race boat anymore. Note that the 18M wings are not rated for more than two adults, either. We've driven it hard (5 adults in 20+), but not trapped out. I don't know what would fail first, but I think it might be the wings themselves. I switched both my boats to SS bolts for rudder pins years ago; much cheaper and stronger IMO. Jsut replace them when they first start to bend. I'd be surprised if it was noticeably faster; the wings add weight and you trap off high; not that much more righting moment. The 20 seems to be limited by bow volume at speed; more righting moment won't help with that. I've crashed a couple of times reaching with normal trap use, and it wasn't because I couldn't keep it flat, it was because I just drove the bow under. Maybe custom wings where you can trap further back...
Anyway, standard 18 M wings fit in between the 20 beams very neatly; back support tube lines up perfectly, but you'll need to make up a new tube/support for the front. You COULD pull them off for racing, and it might be easier/cleaner than doing so on an 18M. The wings are higher than on an 18, so they don't drag when flying a hull upwind or down (great fun for the leeward wing rider when doing the wild thing). Wings also make a great place to mount rod holders. PM me for more details; pics on the beachcats.com