Here is my starting setup for 17.5 2WD - with the new WillSpeed RF3 - TLR 22.5 based buggy.

The track is 84x60, grey office carpet.

The RF3 was designed off of the base 22.5 buggy and stock suspension.

If you choose to run the 4wd arms, some modification will be needed for the arm only. Requiring material to be removed from the front of the hinge area or you can remove an equal amount of material from the front and rear of the arm for a mode 'mid' wheelbase setup. This mod will NOT require an aftermarket C block.