Here check my recent thread review on Mega-Speed remap and a comparison to a piggyback (JBD) http://www.e90post.com/forums/showthread.php?t=724706
Chiptuninng Express is another variation of simple rail pressure trick controller as JBD that I had only more expensive for no reason. Both alters single rail pressure sensor and nothing else.
Retired: 2005 N52 E90 330i Sport 6AT
Retired: 2007 N54 E92 335i Sport 6AT
Current: 2012 M57 E70 X5 xDrive35D