Absolute necessary upgrades
1. TRF dampers
2. Turnbuckle links to adjust F/R camber and front toe
3. Upgrade diff: I personally run M05 ball diff. Others run Spec R or 3Racing gear diff. All are lighter than stock
Secondary upgrades
1. CVD axles - I know some would place this in category one. They make the car more efficient but not detrimental in my opinion
2. Rear 1 degree hubs. Plastic is 2 degrees and chassis has 1.5 built in, so stock set up is 3.5, which is too high in my opinion. I've been running the 1 degrees for quite some time
Set up:
TRF damper
60wt / yellow spring front
60wt / blue sprint rear
Shock length: rear has full length travel / droop, While front has 0 droop (I can't recall how many spacers that makes inside damper)
Suspension: -1'degree camber on rear, 0 degree on front. Front toe is 0 as well. Ride height is 5 mm on rear and 4 mm on front.
Shock position: rear is centre hole, front I tend to change from middle hole to inner hole.
I'm presently running the soft rear roll bar. No roll bar in front. It seems to be helping.
Battery position: I run a shorty battery positioned all the way in the front. I able to do this because I have the R spec axle weights which were never sold alone. Shorty pack is good to have because it lets you move the weight around for the traction you need. You will also want to balance the chassis from left to right, it helps a lot.
Tyres: the m chassis S, M, and H radials are good for track that has medium to low traction. Insert: i use the blue on the S grip and the standard grey (firm) on the m and h compound.
If traction is medium to high, I recommend the Pit Shimizu tyres. They come in 60 diameter S, M, H compound or 55D racing with numbered shores. The inserts that come with them are worthless. I run sweep soft pink inserts in mine
For traction compound I run SXT.
ESC: if you feel you need brakes, add drag brake to settings. Normal brakes are not recommended, because you will swap ends. I have mine set to minimum.
Driving: when entering a turn you need to let off throttle for a second and once its entered the turn apply power, gently, It likes to be driven while on power.
Hope this helps
Long live RWD!