The SIG 1/5th is a great kit, built two of them and powered them with Saito 100. 10' roll and pure vertical. Put a larger prop on it and now still a 10' roll, and good vertical, but half throttle is 100% scale like in both sound and speed. That 90T is a twin I take it, and will sound great. I have a Gemini twin 120 on a GP Ultimate Bipe and it sounds awesome with twin straight pipes.