Coming from a cheaper car culture with whole lot more tuning support at least in the states, OBDII are the way to go. It leaves the end user with so many options to adjust depending on the situation, including fuel grade, emissions testing etc...etc. It also leaves the option to go back to stock if problems arise, plus you are not changing the signals, you are changing the source programing which is far safer.
2013 535i Msport Imperial Blue Metallic/Cinnamon Brown, manual windows, three on the tree, AM radio w/house speakers, Atlas of America!
Future Track whore: 2000 Mustang GT
DIY not CTC!