I am settled on the Pup. I am going to build a fun fighter first with a friend to get my toes wet and then move on to the Pup after. Abu, I ready every single post in that massive thread you linked. While it was informative and got me day dreaming about all the cool scale features I want to add I still have to get my head around exactly what mods are needed to fit the 4 stroker in. From what I can tell you have to cut a hole in to the firewall and mount the engine further back. You then shape the firewall to follow around the engine which is no sticking through where the original firewall was. Is that right?