This has been working really well for me on carpet. My current mod and 17.5 setups are very close.
The TC4 rear arms allow the car to be driven very aggressively without the rear stepping out. There is a bit of work to get them on though. More wheelbase shims are required, a new droop screw hole needs to be drilled in the arms, the arm hinge pins need to be drilled, and some sanding may be required to provide clearance for the hub.
For those that like to play with setup, these arms are definitely worth trying out.