IMO, if you have the Z06, then a stock 370Z should suffice unless you want it to be nearly as powerful for the streets.
The 370Z interior, although not the best thing since sliced bread, is great! The controls are well laid out and simple. So there's no worry about a myriad of buttons of buttons to do simple tasks. On base models, the double-din audio unit makes it a cinch to replace with a favorite 7" head unit. As for the speakers, save money by buying only front speakers and a sub.
Although a pain to mod at times, it's a great car to mod even when it is subtle. It can look, sound, and feel good
Of course, with the money spent on my car I could've gotten something better... but the Z feels at home for me [shrugs]. If it were to be another dream car to replace the Z, I would probably end up going old school with an NSX (really want an R34 GT-R).