I would like to install a chip in an '89 750iL. Dinan offers one for $200 and states that horsepower rises to 326 and torque to 358lb/ft. Bavarian Auto lists one for $400 and I could not find data for performance gain. I was hoping someone might offer any advice on either one. Any input would be helpful especially with regards to driveability and reliability. Thanks and Happy Motoring