The lowest I've had was 24 mpg. Going west through SoDak (i.e. uphill) on I-90 @ 85mph, a very strong headwind, VStream windshield, an intake cam off by a tooth, and the O2 sensor plugged in. Even my brother on my 2000 VFR was getting MPG in the 30's (we usually get about 50mpg on the VFR).
But...