Again I could be wrong about the weight but I remember it being said cause people were questioning how the weight distribution would differ from stock and someone said that it would be getting much better traction because of all the weight added in the rear and someone said that after removing the angle drive and swingarm and what not you add less than 100# when you convert to a quad.
PS It seems like the Fab Factory section didn't make the forum merge, I was trying to find thread but couldn't.
Then I go back to my original statement... 1800 would be amazing. TrakHamr comes in at 1900 with just the 4 wheel conversion. My guess is another 30 lbs, give or take for the turbo kit. Not sure how much difference there is between the G35/Z350 vs the C4 Corvette... but I can't imagine it would be upwards of 100lbs.