Equivalent spec for spec, a JCW car will always fetch more than a standard. Market forces will always deem there to be a gap between the two, just as there is between a cooper and a one or a 330i and a 325i etc. etc.
The previous ( R53 ) JCW didn't keep much of it's value because it was overpriced compared to aftermarket tuners. This 192 kit is value for money so will definately perform better financially.