Need buying advice.

vtec to vvel

there's alot more to it than just good credit, sign, and drive. and you need good credit whether buying new or used if you want favorable interest rates/deals.

New Car Pros:
-COULD have better peace of mind than used (your comment about no risk of car problems isn't necessarily true - some new cars could be lemons).
-you know what has/hasn't been done to the car.
-you know the car history.

New Car Cons:
-depreciation
-depreciation
-depreciation

Who knows, the OP could be a brand new Z and then Nissan could come out with a hotter model and the OP could want to trade soon after, which in this case, would be extremely unfavorable for the OP since s/he would be so upside down on his/her loan, unless they have the $ to make up for it.

btw, i would NEVER buy a nismo, or a brand new car for that matter, with 100 miles on it. 100 miles is quite a distance and you never know what those previous test drives could have included.