You will need a modified gear diff with extra washers or a TA03 ball diff. The oil gear diffs do not fit the MO3. Plus they usea bigger 1510 bearing in the chassis. I would also invest in hardened outdrives for the ball or gear diff.
I have been runnning my MO5 V1 in swb configuration at Newcastle and Tamworth cup. I have found that by turning down the servo speed has made my car less twitchy and easier to drive. I am using Mc38 front and Sc32 rear tyres and a rear swaybar. I have the front shocks second outer on front tower and run 54000 shocks. Using Tamiya fluro red springs front and rear, plus added extra weight to my battery. 50 gms of lead sheet.
I found the best body with these tyres to be either the abc hobby swb swift or Blitz C30 volvo with no wing.
I run front toe out and 1.5 degree rear hubs.
It working for me. Just need to get the radio setup to make the car easier to drive.

As usual what works for me, might not work for you. It should give you a ballpark to begin with. Test and adjust from there.

Later,

50 cal.