Because of the fact you are mounting a medium case engine in the plane, no, you will may need to use the spacer in your plane. That said, due to the light weight of the engine you are using, you may want to use the spacer. And some lead. I got mine to balance perfectly with a Saito 1.20 in it and did not use the spacer. I think that the 1.00 will be a good engine for you, but take your time and ensure it balances correctly. If you get it nose heavy it tracks very well but bounces badly on landing, tail heavy it responds well but floats really bad when you go to land and still bounces badly. When it is right your landings will tell you.