that servo is probably better than the stock rtr one, but not really great for 1/8. more a basic replacement for a 1/10.
with the savox a 1256 (20kg torque) would be great, you may get away with a 1258tg (12kg)

Yeah gonna upgrade the servo, my buggy came rtr with the savox so its not bad I guess but the horn was crap. Plastic servo horns wont last.