The Dash 8 100/200/300 has normally a standard TW limit of 10 kts, but with special supplement that was of course flight tested up to 20 kts may be used. Use of this supplement is limited to higher flapsettings because otherwise problems with brake energy (also for take-off -because you must be able to stop with full braking) and possibly controllability could happen. I don't think it would be practical to have even higher TW components. Already with 15 kts tailwind take-off, you need a strong copilot to push down on the (unpowered) elevator.Only recommended for "oneway airports".