that Tower servo is $28... the bluebird servo that has metal gear and hi torque is $22. in this case i don't know how both of these brand perform, but i will be likely the hitec 475 or the bluebird because they are cheap. as for flying the F40 two years... that was wrong... i flew the F40 4 times before it hits the ground because of radio OR machanical problem. the reason i'm going w/ the harrier 90 is because that F40 doesn't look like it can take the full speed off the Super Tiger 90. as for the Harrier 90 it is designed for a 90 engine. so if i go fast and rip the plane apart w/ the 90 engine i will get a new one! ... what do you guys think of the harrier 90 as my choice? and servos selections... i still need help on that... cheap servos but hi torque and good too. high speed would be good too around 60*/.15 sec. i still need help so please offer any advice that u have. thanks for the comments