I installed a friends brand new OS 55AX and a 12-6 APC to my GP Big Stick 40 for break in. WOW!! I could barely hover it at 95% throttle with my OS 46 w\12-4. The 55 will hover it with ease at only 50% throttle and accelerate straight up. I may not give it back. I think he should use my 46 on his SIG Somthin' Extra until his skills catch up. Whatcha think?