The wr250r/x has a rev limiter. It won't let you over-rev the bike.
First gear is good for about 15 mph (you do the correction for kph) I think.
Wind it out and when you feel the bike have a massive hic-cup you've found the rev limiter.
As for crash protection....a lot depends on the crash. I low-sided in a parking lot and the only thing scratched was barkbuster on handlebar and footpeg.
If the crash involves more violent actions by the bike - all the crash protection you can buy for it won't save it from a lot of damage.
Bent handlebars are quick to happen. Scoffed or broken plastic, bent sub-frame, broken lights, twisted or bent forks.....it all depends on the situation of the crash.
Keep the rubber side down.......
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2008 WR250X
Gearing: 13t - 48t
Power Commander 5 / PC-V
Airbox Door Removed - Flapper glued - AIS removed
FmF Q4
Bridgestone Battlax BT-003rs