you might try testing the stock gyro to see if your alien gyro is causing problems. if it still flies funny, you may have too much pitch.

as a last resort, you may want to upgrade the tail. many ppl who have a brushless main motor also have either direct drive or dual motor tails to help cope with the rotor-torque a brushless main motor can produce.

don't give up yet. if all else fails go back to the stock setup and have fun flying it for a while.