Vader/Condor 150, best engine upgrade?

[ProDigit]

I initially bought the Vader 150, because I needed more power than what my roketa MC05 127 could offer (125cc pushrod).

I like the pushrod engines, they have a lot of torque, but not a lot of top end.

The Vader 150 has a much higher rev range than the roketa MC05 127, but in some way it's still limited. It's not an actual 150cc, but closer to a 138cc.

I was wondering if there are actual 150-200cc replacement engines for this bike? I know there's a 250cc replacement engine, but that's a bit too much for me on this bike.
I'd prefer maybe like a 190cc, like on the Vader 125 upgrade, but prefer plug and play, bolt on replacements, where I don't need to manufacture any mounts or any unusual electrical mods.

Which ones are the best engines?