I have been flying MVVS 26 + pipe in a 2x2 stunt for a while and I am also looking for a little more punch.

DL30 seems to have around 3hp without pipe so not much more power without pipe(MSS with pipe has a bit more actually). Side carb is big no no.

Syssa seems to be nice rear carb, rear exhaust engine, but there are so few user reports that I will wait for those.

Generally all these engines need a pipe and modern pattern planes don't come with pipe tunnels anymore. They are designed for short Hatori headers and that's it.

I hope YS announces 200 CDI gasser soon