Does anyone know how hard it is to change a Naish 2015/16. Below the bar depower to above the bar.
I find it hard to get the leverage below the bar to depower compared to above, and also during depower when the wind has dropped off a bit and kite not fully powered hard to pull the rope from the cleat and get the right angle to release.
Would it be an expensive exercise for the above the bar differences.

I have both Naish btb and atb. I prefer the btb and don't have an issue with the trim anymore (get used to it). Is it a fusion bar or a torque that you have. Maybe post a pick of your current setup to help. I have had to pull both to pieces and reassemble. There are some good instructional videos on youtube on replacing Naish bar trim lines. Watch these, note the parts required and source from your local kite shop or fixmykite.com or similar.
I would think it would only need new line arranger, line stopper and safety line and maybe different trim line.

Once you've attached the front line trim system to your current front lines your line lengths will be totally out and you may not be able to correct them without additional extensions etc.

By the time you buy the parts and install them i think I would be easier to sell the older and buy a used ATB

Or you could find a similar set of bar and lines and swap out the BTB with ATB but that would be pointless as he front lines almost always wear before the rear