if you have machine to measure magnetic strength of the rotor, look for these numbers: 1200 to 1300 gauss for good balance of torque and rpm (1200 tc or 2wd buggy and 1300 for 4wd buggy or technical tc track)
1100 to 1200 gauss for 12th (1s application)
1400+ gauss good for show off but very inefficient lots of torque, low rpm and high running temp.
1100 gauss or lower dying/bad rotor.

are you running tc or 12th 17.5 or 13.5?
for 13.5 or 17.5 or higher turns these are my recommendation
get short stack stator and high torque rotor for TC
short stack stator and high rpm rotor for 12th.
for 10.5 bandit is really good. 8.5 or lower LRP, Reedy or V10 Gen2 are good/smooth power and good rpm.

Thanks LEEE