I'm lucky to be able to own both cars right now so I thought I would throw in my 2 cents. Don't take anything I say too personal - it's only my opinion I love both cars!

STOCK vs. STOCK:

Exterior looks: All personal preference - both cars are headturners in their own ways. I seem to get as many "nice car" comments in both cars. My favorite color is blue, and I love the Daytona blue on my 350Z.

Interior: I prefer the S2000 interior over the 350z. I'm not a big/tall guy so the S2000 fits me like a glove. The S2000 has a "tight" cockpit feeling. I can see how someone bigger would be uncomfortable in it though. The 350Z is definitely roomier.

Handling: I've been an auto-xer for close to 2 years now. I prefer the nimbleness of the S2000 over the 350z. I think someone mentioned the S2000 being too twitchy, and I agree. It took me a lot of auto-x seat time and plenty of spinouts before I got comfortable or confident in the S2000's handling. The handling in the S2000 is more raw and quicker than the Z. I also used to own an EVO and the EVO's handling is the fastest of the 3. The Z isn't "heavy" by no means, but when you compare the S2000 and the Z, the 350Z feels like a boat IMO.

Power: The torque in the Z is awesome. It's nice to be able to just cruise in 4th gear and mash the gas and the car actually goes! The S2000's motto is "power is just a downshift away" Most know that the S2000's power is in the higher RPM VTEC range (6-9,000) for the older S models(which I have, '02).

Transmission/Gearbox: S2000 wins hands down with the best gearbox. The 350z's gearbox isn't bad, but I prefer the S2000's much more. The shifts are shorter and more direct IMO. A lot of times, I take the S2000 out more just because of the shifter.

Reliability: About 27,000 miles on my S and haven't had one problem. Many of the those miles are hard auto-x miles also. Close to 3,000 miles on my Z and no problems yet also <knock on wood> I do not launch either car though.

Comfort: The 350Z is more comfortable to cruise around in. More room, features, etc than the S2000. The 350Z is more of a "luxury cruiser" when compared to the S. The S2000 is more raw (loud engine, harsh ride, no heated seats, etc. etc.). Maybe because of the extra weight, size, or traction control, I feel much safer driving around town in the 350Z.

Fun factor: S2000

Both cars are great in their own ways. I know a lot of people like to compare the 2 for whatever reason(both 2 doors, etc.), but they are both VERY different cars. For the S2000, I think you're either going to love it initially or absolutely hate it - there's usually no in between.

-Brian