RE: Saito 180 good 3d engine?
The only great 20cc is the DLE. At 30cc two are great, Syssa SAP180 and DLE30.
There is more to gas engines than just looking at the cc's. The DLE-20 is a bit more power than a Saito125.
The DLE-30 is just a bit more power than a Saito 180 and more responsive.