Getting ready to order some parts from A-main. Is the FT lightweight rear topshaft worth getting?

Also, I see lots of folks here are running the rx-8 and sc4x combo. Care to divulge your esc settings and # of pinion tooth? Running all stock setting on the esc and 14tooth, the temp on the motor got to 160d after a full pk, so thinking I'm about right on the gearing.