i used to have a lil VW passat, 1.8 turbo with a 5 speed manual
i had the ECU reprogrammed so instead of spiking at 7 and holding at 5 psi, it would spike at 19 and hold 17 all day long
my wife could get in the 40mpgs with that car all day long, i couldnt stay out of boost and consistently dropped her down to 20s