LP-8 Magnum. -Y
If Diana had to take a proven winner and adapt it to EMS I'd prefer they go with the 350 or the 460 and leave the proven side lever platform as is. I am NOT a fan of gas springs and I prefer the coil springs and center latched pistons.
I'm personally not seeing the appeal of the EMS. Especially with proven models. I bought a D34 EMS strictly for the threaded muzzle and the plastic stock. I wanted German quality in an ugly duckling package for my aging dad to use in the barn w/o dinging up prettier rifles.