My vote go's to Evolve, best all around performance.
The Harrop would be my second only due to the low end, but i see too many high rpm drawbacks and its not out yet.
If all the kits offer the same top-end, but one gives you more low-end, none as much as an N54, but significantly more, then the decision should be easy.
Consistancy is another factor. Looks are subjective, but...
Easy choice..
@Mit_Boost illustrated my sentiments as well.