I’ve been trying on the forums looking for ideas on what I wanna put in an EXB build. I recently looked over these servos. Depending on the weight of your Kraton and the tires you wanna use (MT or Slicks) I personally go big. The Arrma ForumsRC build logs are https://www.arrmaforum.com/forums/rc-build-logs/

Reef's RC REEFS03 - 555HD High Torque Digital 7.4V High Voltage Coreless Servo https://www.amazon.com/dp/B07ZDHTKJG/ref=cm_sw_r_cp_api_glt_fabc_1H9P4HV1FBKDBRYSHH6J

JX Servo BLS-HV7146MG 46kg Brushless High Precision Steel Gear Full CNC Digital Servo Motor for RC Car Robot Arm Helicopter Airplane Parts https://www.amazon.com/dp/B07PTYTMJL/ref=cm_sw_r_cp_api_glt_fabc_J3DER73EB5QHSFAXFK2D

Also look at the dimensions of the stock servo and compare to possible replacement to ensure proper fit. Whichever you decide to go with be sure they come with a servo horn or two, I think Armma is like 23T vs the standard 25T.