Hi and welcome to the forum :greetings-wavingblue: as for performance I would do a remap more power and better mpg.definitely worth the money just use a reputable company, as far as sound goes the RCZ is a little lame and your only going to sort this by getting a custom exhaust system, this isn’t as expensive as it sounds
there are off the shelf aftermarket rear systems but these don’t give that much of an improvement in sound. To get some real noise the centre box needs removal.
Hope this helps and try and get some photos posted of your Z we never grow tired of seeing these beautiful cars :beer: