And change the top rose joint as the RS125 uses a 10mm bolt and the NSR a 12mm one, unless of course you think Honda were wrong to use a 12mm bolt and a 10mm one will do the job fine.

And the remote res doesn't clear the stock subframe/undertray/battery box.

So, apart from being wrongly sprung, wrongly valved, wrong top rose joint and not fitting in the supplied space it's a direct swap.
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