It may be safe, but keep in mind that your '98 Disco has a 1960's era 215ci Buick engine that has had some work done and an ECU installed, but it is still the same engine. So I personally would not run ethanol in it. That is not to say that it wouldn't run and run great, or that someone has run it and had no issues. Of course I also know people who have nothing but issues with their Rover and haven't done any off roading nor have they done anything that would be hard or abusive let alone run anything but 92 octane. So take all that with a grain of salt and flip a coin and keep good records and try it...