I know "chip" tuning is a popular modification for cars. I've read the promises of efficiency and power gains. I haven't seen anything like it available for FX50. The FX50 has the most computer technology of any car I could find. The Mercedes S Class has better full-vehicle tech integration and a better interface, but it actually lacks a number of great features. I don't think there would be another vehicle with better electronic timing or control. Infiniti will lean more towards efficiency than performance, but there's tradeoffs either way. I'd suggest to use the stock settings, and if you want the slightly better performance, fill with the highest octane gasoline you can find retail so the chip will adjust timings itself. Maybe the Invidia guys would know what to do. Changing the exhaust for more airflow can make the stock settings less efficient.