I have a RaceChip Box/cable which I purchased a year ago for $300 (including shipping) which is for sale now. Good noticeable power gain (specially 2K RPM and up) with no CEL errors. Here is a link below for more info:
Serial condition RaceChip Without RaceChip Tuning Changing Power in kW 103 kW 129 kW + 25% Power in PS 140 PS 175 PS + 25% Torque 320 Nm 390 Nm + 22%
For sale for $200 or best offer. PM me if interested.