you need about 30-40% more fuel with the e98 e85 fuels, but the price difference more then makes up for it. You still save some money when using the "E" fuels, although the initial investment is higher because of the large injectors and the rest of the fuel system.
But you are also not destroying the ozone, and you can make more power off the E98 then C16 or c23, and comparable to VP Import.
Last I checked, 5 years ago, a drum of vp import was $1200.
The muscle car guys are making 1400 hp on 250lb/hr inj and ~900whp on 150lb/hr (1600cc) on "E" fuels with 8an lines