KO PROPO PDS-2366 ICS
6v high torque power, digital servo feat FET (i.c.s), alluminum heat sink version
£130.. $250

very good, i had it in a savage...lol

buy a servo with a fast reaction and torque control, i over paid for mine a little but...it does the job, i would suggest you buy the best you can, i would go cordless, means a faster response, and metal gear are sooo much stronger, they dont break under big force and torque..

hope this helps...