Crankshaft 5th central screw

Hi, guys. I'm about to change the ZR on my Audi 80 convertible. It's a five. But now I have read that the central screw with 350/450 NM is to be tightened. Since my torque wrench only goes up to 320 NM, the battery impact wrench I want to increase but up to max. 539 NM goes, I thought to put on the central screw with 539 NM, so without the extension of VAG. I don't think you can do it with a hit wrench. Is the screw carrying this or is it too much strained? The screwdriver has different levels that you can select. Either 431 or the 539 NM would be near the 450 NM. Just don't exactly have the 450 NM.......have no desire to add a torque wrench that can make the 350 NM because the impact wrench comes on everyone. And I would also like to do it myself because more conscientious than an unmotivated mechanic who has no balls.........