I have recently started looking into performance chips, and have found a few different ones. I found this one made by Surge
http://www.myhotbmw.com/bmw/Surge/Performance_Chips/BMW_Surge_Performance_Chip/533052
and was wondering if this does everything that it says it does (boosts fuel economy, up to 35hp gain, will NOT void warranty, will NOT damage engine because it stays within manufacturer specifications.) this chip is selling for $89, and i have seen others for up to $400. should I be wary of a chip selling for this little, or would this be fine to get for a decent gain and a fun drive without hurting the engine?
http://www.myhotbmw.com/bmw/Surge/Performance_Chips/BMW_Surge_Performance_Chip/533052
and was wondering if this does everything that it says it does (boosts fuel economy, up to 35hp gain, will NOT void warranty, will NOT damage engine because it stays within manufacturer specifications.) this chip is selling for $89, and i have seen others for up to $400. should I be wary of a chip selling for this little, or would this be fine to get for a decent gain and a fun drive without hurting the engine?