Welcome! I don't think you'll have an issue picking up the stick. I don't know what your price range is but a Touring/Sport would work out well for you I think. The touring will let you keep some creature comforts you have gotten used to driving the Infiniti and the sport package will give you all the sport goddies, bigger brakes, wheels, spoiler.
I wouldn't limit your self to the Nismo exhaust, some one correct me if I'm wrong but I don't think it give huge gains and is rather expensive. I personally have the ARK Type 2 and love it, but some others that are popular are the HKS which AK has, Berk, and Fast Intentions. If you go with the sport package I wouldn't worry about a big brake kit unless you plan to track the car in which case an oil cooler should be on your list.
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