SL/R230: PERFORMANCE PLUG-IN CHIPS



I have ran into advertisings for modules to plug in the OBD2 claiming to improve power and fuel economy by 20%. I wonder if any of the members have used those and what has been their experience with that gizmo.!
Thanks!
Most curious to hear good stories from those that have only done the ECU tune (perhaps to consider their other mods in the future).
Many thanks!






