WR250R big bore kits

Is a 290 kit upgrade really worth the return you would get? Everywhere I read is people complaining the bike is underpowered. I’m wanting to be able to do gnarly tight wet singletrack and then be able to buzz home 30 miles at 65 mph. Is it possible? Thanks

A stock WRR (13/43 gearing) can do 90 mph fairly easily. Even if one massively gears down (e.g. 13/52) for single track, the bike can still do 65 mph comfortably.

The problem with the WRR and single tracks is its weight, not its engine.