anyone dyno the greddy evo 2 looking in to buying one but dont want to loose power the nismo is the other option but not surewhat gives better power or sound tone

 

the gains on ANY exhaust will be within a couple of hp of one another. True dual like the Greddy or a Y PIpe + Cat Back like the NISMO produce nearly identical results.

What differs is they way they look, install and sound.