I customized my one-way to be a solid spool with a little dremelling, drilling, JBWeld and some pins. I then set the rear diff with 30,000 (help turn in faster_keep it loose_unless your track is super fast). I swear, I don't know how I ever ran without one. I loved my one-way but even with the car tweaked to perfection, I couldnt break last second down the straights. NTC3 were taking me on the inside. And us K-car guys can't have any of that.
Now I can hit the breaks within the last 3-5 feet of a 200 ft straight. If I wanted I could even start turning in while breaking and with my Rody V12, I shoot straight out of the inside line blocking anyone to pass me.
It changes your driving style but it's easier to race than with the one-way. You can blimp throttle it through the whole turn to keep the engine from loading ... and then BAM!!! full power out ... shoot for the next turn and dive like a mo-fo.
I had the same probs with oversteer. I slammed the engine as low as possible with a Kawahara micro clutch, put a flat AAA pack all the way forward on the chassis with a RTR NTC3 fuel tank on top. I used the RTRs tank because it's longer and lower than the Factory Team tank. Since the tank has 3 mounting screws. I used a Serpent 950 battery holder upside down, screwed to the TC3 tank and modified it to also mount my AMB Trans at the bottom too.
Lower your throttle servo to about .03mm above the bottom chassis too. It doesnt really matter if your throttle servo isn't in a laydown LC position like the new RRR, because the bulk of the weight of the servo is in the motor which on most is located at the bottom of the case (except for HiTech Servos_they're just plain heavy all around). And if you have to mount your reciever and wires above a laydown servo. You really defeat the purpose of the Lower Center of gravity idea anyways.
Set front toe to 0 with 10 degrees of caster. Camber is about 1.5mm. You won't need much camber up front since the caster will set you in the right wheel angle in you turn in.
Ride it at 4.5mm front, 5mm in back. The foward lean and the new front weight of the battery position will help drive the front wheels in the ground (solid spool).
I cant figure how to post pix up in here, but if you can help me out, I'll post them tonight when I get home.