i've run the xcelorin 10.5 only once...
on a short-medium sized track, carpet surface
this was geared at 6.39 and 6.56 FDRs, LRP TC Spec ESC with brushless profile set between 3 and 7 across a number of runs..
compared to the LRP 10.5 Stock Spec motors, the Losi seems to lack a little bottom end punch when geared to match top speed..
to me this is the difference in power and the resulting torque..
LRP = 255W vs LOSI = 225W
thats 30W difference which has to generate more torque
also there is a vast difference in the kV ratings of the motors..
LRP = 3800kV @ 7.4V = 28120rpm
LOSI = 3080kV @ 7.4V = 22792rpm
i am going to try retarding the timing a little (maybe 2 degrees, hard to tell as there are no markers on the can!) and see if that helps the bottom end..
but i think ultimately it may be a losing battle against the LRPs