Would these be good mods to start with?

wheelspeed

I like ABM's advice. You just got the car, and you got the top version with all kinds of goodies already on it. Just enjoy it at least for one summer! Doesn't the Nismo already come with a better exhaust?

If you do things right away now, won't you get bored in a few years with nothing left to add to it?

It's likely a 'problem' with many models of cars... the higher the performance model you buy, the less options you have for reasonable, effective mods you can add. All the low-hanging fruit gets taken.