The porsche 911 tt 4WD weighs around 1550kg (100kg less than the murcielago), but handles exceptionally well. And that is because the tyres do grip around the corner...
Do you remember the Diablo SV? It was similar to the VT, except that it was RWD instead of 4WD.
And the difference in weight? The Diablo VT weighs around 1650kg, the SV around 1500-1550. Around 130 kg of difference.
By adding the 4WD, the Zonda would weigh 1380kg or something similar. And it would handle even better, possibly better than anything else on the market, due to its light weight as a 4wd (something like 1400kg is still light for a 4WD), AND the tyres would be able to cope with all that torque.
http://www.autodrome-cannes.com/index-eng.asp
Visit this website. It is a Pagani dealer. It states that spec-wise the zonda beats the Enzo, being that the Enzo is 100kg heavier than the Zonda (at first I could not believe it: The Zonda has an incredible and luxurious interior, full of leather, while the Enzo has a dull carbon fibre cockpit!), and guess what, the Zonda has more torque than the Enzo! However, the Enzo has more hp. So who wins spec wise? The Enzo is a track-car, so its suspension are track tunes, not road-tuned, and thus it handles better than the Zonda. However, solely based upon the stats, the Zonda is faster than the Enzo, because of its Weight and torque! If the Zonda could muster another 70hp, thus making the total hp output to 630hp, then it would be faster than the mclaren!
And if you read the articles there, there's a comparison between the Zonda and the Enzo (not spec-wise, but a real test), and the Reviewer states that the Zonda feels composed even after 200mph, while the Enzo does not, and this is a real achievement!
AND FINALLY, did you notice that this dealer (autodrome) can make you order a Zonda which sort of has a "Sports Optional", which increases the hp of the Zonda to 600hp? At 600hp, the Zonda will surely beat the Enzo in a straight line, and the Mclaren too!