gashuffer,

On the MO3 I build the TRF M Chassis shocks as per instruction, including the "o" ring. For a MO5 I omit the "o" ring. You have options with regards the pistons:

3 hole 50 wt oil front 40 wt oil rear
3 hole 60 wt oil front 50 wt oil rear

2 hole 40 wt oil front and rear
2 hole 30 wt oil front and rear

Comes back to how you want the car to react.

Happy racing.

Regards,

Calvin.