Phoon, your questions are more suited for Cybertom and Ed at this point. I just began going through my kit box last night. One issue that I believe may be a problem is the width of the DA. I'm not real familiar with the engine but most gassers I've seen have the muffler on the side, which adds considerably to the width. The cowl on the "Tiggie" is rather narrow. Certainly less than 6". Your need for more power is evident. Have you considered the Laser 180? From what I have learned - dimensions in a previous post - the engine will fit the scale cowl. As for mounting the engine, you are correct in assuming the engine mounts on rails. A firewall mount is do-able with an increase in the thickness of the firewall and strengthening the firewall mount structure - more weight. The current mount rails pass through and secure to the front 3 bulkheads in the nose. The additional weight with the DA sounds to me like you will be needing tail weight. Not something you want to do with your flying site situation. I believe Ed stated that he used less than a pound of nose weight to get the CG at the recommended location. More power with more weight will be a wash out.