Best place ato mount it is about 1" above the turbo to exhaust manifold mounting flange, this is known as pre-turbo( most acuurate), you dont even have to take turbo off, you get ya some good wheel bearing grease, dip your drill bit in it, drill alittle, then clean it off, then dip it again, do this over and over until done, just don't get greedy on drilling to far and let the grease get really dirty when you are just about to drill thru, then do your tap the same way, then take a small mechanics magnet and run it thru hole to pick up any shavings that might be around edge of hole, installing probe is cake walk. Good luck