take the blank piece out of the stock airbox and put a filter in there and youll have a nice sound that people also dont expect
my fuel economy is pretty shit as well, the dealer suggested i put some injector cleaner through it (car is at 100k) and this might fix it. but im haing gearbox problems - dont worry it doesnt seem common at all - and they think its either a misfire due to fuel (lack of or too much) or a torque converter problem.
anyway, im hoping its a fuel problem so my economy gets better!!
and feel free to go on about them, we already know they are an awesome car