The kit engine has its short-comings, but if you use reference pictures to add detail it will look pretty good, especially if you use the kit air filter system. The kit engine has internal injectors. The resin one has external injectors (at least the connections). Dan may offer that engine with or without the blower, I'm not sure, and I'm definitely not an expert, but from what I've read, the "hey-day" for that engine (with the blower) was the 50's although they were used in the 60's some as well. As I said, if you want to use that engine, there is the possibility that one was installed in a glider.
Please don't think that I'm trying to be critical, but I though you might want to know that the two engines were actually different engines and that the resin one was based on an early design. Someone can correct me if I'm wrong on this, but I think the kit engine is 855 C.I.D. and the resin one is 743 C.I.D.