There's pics already of the single having the outer raised deck being flat, with the center of the deck raised for the single. Only time will tell if the new 4-stroke motors will hold up to getting beat up in the middle of the tunnel. Since the design of the boat is not intended for big water (62" wide tunnel w/ 99" beam, 15" deep tunnel, 28' 6" LOA) , I think the motor will hold up ok. These will more than likely be used as flat water rippers (like a big STV/Mirage), not a bigger water boat like a 28 Skater. I've been in Dan's 28, and it's great in smooth water, not so great when it get's lumpy. I had my last 28 Skater still when he first got his 28, so it was easy to see the difference running together.

With 300XS on both hulls, how much faster is the DW28 than the 28 Skater?

I saw a short youtube vid clip of the 28 being towed with all the PBC boats and it looked like that hull is set up for a single, but can't be 100%. Skater30, I don't personally have SOB experience with a true tunnel, but a lot of my friends started with 21 Skaters back in the day and they were notorious for destroying gearcases, and that wasn't in rough water. FYI the 28 Skater with 2.5s in your pic was originally a Washington boat, from Bremerton. There were a lot of Skaters up here in the 2005+ era.