4 wheel steering. these little rigs are stellar out of the box, but there is lots of room to upgrade. So far mine has:
-Custom bumpers w/ 1oz weighting (each)
-partial 4 link conversion (lower links)
-Custom center skid plate
-Axial Wraith 108mm wheels with 1oz each up front and 1/2oz each rear.
-Dynamite Tazer 280 motor
-Losi high torque servo (have 2nd for rear)
I'll be doing a full on 4wheel steering conversion this week. Just waiting for the new receiver and transmitter
@r8herhed5150 has a write-up for a much cheaper (but also more limited) 4wheel steering mod. I am going full bore with 3ch receiver to allow for independent front and rear, combined front and rear, and "crabbing" Which I will be writing up as It happens