airlordz, are you looking into the G35 Coupe or the G35 Sedan? I can tell you that the G35 Coupe is a great car and since you probably already know that, I'll tell you some "flaws" based on my experience with it up to this point just so you know the real deal on the car.
-It's way more tail-happy than it should be.
-Seat backrests are manual recline. This isn't so bad but when you let someone into/out of the back seat area, you lose that recline setting you prefer and you'll be fiddling with the manual recline for a little while until you get comfortable again. The front seats in the car are awkward, they are angled backwards a bit to much.
-Worst seatbelt in a car I have EVER experienced. Doesn't matter how tall or short you are as the seatbelt is not even adjustable, after a few minutes into your drive, the seatbelt will be pulling and tugging at your neck, causing you to constantly adjust it.
-Trunk space is limited....not just in overall room but the height of the trunk is very shallow also. You CAN fit two sets of golf clubs in the back but it's so tight that Infiniti has a diagram on the inside trunk lid showing you how to do it (I don't play golf so this doesn't bother me). Fortunately, the rear seats fold down to open up a whole new level of practicality.
-Rear seat room overall is very good; legroom is great and two adults can fit very comfortably back there unless they are tall! The low roofline of this car allows for VERY little headroom in the back....if you have any passengers over like 5'7" you can forget about putting them in the back unless they don't mind slouching down or bending their heads forward a little bit.
-Interior is definitely made up of bargain-basement materials. You can replace the whole interior aluminum trim for literally about $50 at the dealership.
This all I can think of for now, and obviously I'm being very critical. The only parts of that list that actually bother me are the manual recline on the seats and the annoying seatbelt.
Here's my actual opinion on which direction I think you should go:
I feel like the 325Ci would be a more livable car, so you should sort of base your decision on how long you're going to keep the car. If you plan on keeping it for only 3 or 4 years, then the G35 Coupe is very convincing as it offers really great bang for the buck. But if you plan to hold onto the car for more than just a few years, the 325Ci would be the more "practical" choice as it holds its resale value better and is much more "livable" (based on the points about the G35C I mentioned above) unless you just can't pass up on the G35C's styling and power.