You May be best going down to the club/track you race at to see what everyone else is using on their Laydowns or have a look at the setup sheets on the Schumacher site to see what the pros are using on your intended track surface as a ref point.
The upgrades I currently have on my laydown are; Brass radio tray, under servo weight, Trishbits shin splitter, Alloy 5 degree yokes + hub carriers, Alloy link mounts front and rear, Alloy centre track rod V2 + radius arms, Rear ARB, 3 plate slipper conversion, CNC idler gear & U/J drivershafts.
The upgrades have been added over the last 8 months of racing the car starting with the brass weights as these gave the car better handling/traction. I then started adding the speed option alloy parts to the front of the car for strength and better steering responce.
The rear of the car saw the last of the upgrades with the CNC idler gear, 3 plate slipper, U/J driveshafts and rear ARB.
Future upgrades may include the X-Brace conversion & battery cradle + the alloy differential gear once the current one has done its duty.
I use the car for both indoor club meets and astro racing outdoors
