I have been running the Cirtix Stock Club Race combo for over 5 months and won Cirtix Series Race in TQ RC Racing. From my experience, Cirtix combos is competitve only if it is run against other non-boost ESC with non-timing motor. It does run cool and can be geared extremely tall. I gear anywhere between 3.2-3.5 without heatsink on my motor and never really got past 160F.
However, the 0 degree timing-locked Ultra Sportsman V2.0 is no match for other timing-advanced motor. This motor has plenty of speed but at that gearing, it lacks torque. At TQ RC Racing, it is at least 1-2 seconds slower per lap against other motor cranked with max timing . I have not tried to alter the timing because I feel that this is not what the motor is designed for. I will probably try Cirtix ESX and Compeition V3.0 motor at max timing to see if there is any difference.
KO PROPO just released an affordable ($155 including motor, ESC and handheld programmer) BLZ-350 with locked 0 degree motor. This would make for TRUE SPEC RACING with no-boost and no-timing ESC-motor combo. I think we should allow these combos to run together instead of allowing timing adjustable motors.