After >100 flights with a lighter Saito 91 (22oz vs your DLE-20 at 33 oz), I made a turn back to the runway after a low altitude deadstick and landed on my "chin", flattening the main gear and cracking the firewall loose. After digging in to the front of this airframe, I would agree that something as heavy as a DLE-20 would do well with some extra support.... maybe hard balsa or even maple tri-stock behind the firewall. Having essentially removed and replaced the firewall, I noticed that its really only supported by the fuselage sides- the top and bottom surfaces are such light ( thin and soft) balsa that I doubt they lend any structural support. What's more, mine was glued to the flat fuse sides well enough, but the firewall itself split open to reveal that its made of layers of those "tropical hardwoods" commonly found in Kmart furniture- not real birch or lite-ply. I'd consider putting some gorilla glue around the back of the firewall or replacing it with 1/4 Birch ply for a big engine. This is a very lightly built plane that fly well light, but...
Hard landings can easily put 3-5 G's on the engine, so that can can become 6-10 lb load with that 2lb honkin engine and I'd hate to see it fall off during a hard touch and go! Then it would be called a touch and "Doh!".