You will most definitely wind up with lower resolutions and/or frame rates.
Any time you emulate a system in software, you can expect to dramatically reduce the overall speed, and I don't believe that current hardware is sufficiently blindingly fast to run FU1 at 1024x768 at a reasonable frame rate via DOS Box. It's probably not even close.
Do experiment -- you might be pleasantly surprised -- but I would keep your expectations on the low side.