I'm gonna have to go for the GTR, drivability wise, its the man. Like I think Razor already said, it has ATTESSA which is undisputidly the best AWD system on the planet. its TWO POINT SIX LITER engine has been seen pushing 1,000hp in tons of cars. The most powerfull one was I think the HKS car with 1,600hp! Out of a straight 6 2.6l i'll remind you agian. The RB26DETT is remarkable, ATTESSA and HICAS are remarkable. Check out the skidpad work, its crazy!
Now if you want to compair the two modded, once agian on a drivability level. Ask youself this. You enter a 70km/hr turn doin 140km/hr. You reach the apex. You yam on the gas. Would you rather be on a sure footed, computer monitored (10 times a second) AWD system that can split torque 50/50 to control your 700bhp? Or do you want your back tires to light up, kick the rear end out, and send you spinning into a tree and wrapping your brand new Farrari around it?
Ok ok, mby thats a little extream, I'm sure a good driver could drive the damn 360 around the curve, after all, it is a Farrari. I just think that on a road course, godzilla would blow the Farrari's doors off!
Ok, now what about parts? Farrari parts... Expensive, hard to get, takes FOR EVER to get them.
Nissan parts, depending on the part, you may be able to order it from a local HKS, Apex i, or even Nissan dealership. If not, just get on a NZ website and have it sent. And a bet you it won't cost as much to replace a stuffed axle on a skyline then one on a Farrari.
And now back down to earth were money DOES matter, I don't think I need to say any more then this. Nissan Skyline R34 GT-R V-spec: $50,000.00~ US Dollars to buy in Japan, $85,000~ US Dollars to get from MotoRex here in the US. Oh, and have you ever tried telling your insurance company this one, "Yes hi, I just bought a new car. What kind? Oh its a nice new RED FARRARI"
But when it all comes down to it, its a matter of personal taste, Hell I'd murder small children for either one of um! J/k Mby not small children, but old ladies yes.