Ok Being a truck driver over the road can get boring after a bit. But each day is a new testing day in my mind and finding the best performance from our rd's is always priority for me. I just completed about 7400 miles the last 2 weeks and ran one STI vertically and one in the normal horizonal position. I know 2 on at same time is a no no blah blah blah but.. I spaced them apart alot (width of a semi). My findings were consistant daily. VERTICALLY MOUNTED YOU LOSE OFF AXIS ALERTS, the more off axis the more u lose. Straightline sensativity seems to be the same. K-band falses from radar doors is more often but does not give any more sensativity from real LEO K- band encounters. With both STI's horizontal performance was awesome and both alerted within 1 second of the other on 95% of encounters. Bottom line KEEP IT HORIZONAL. I know we have had other post about vertical mounting, but I felt you would all like me to share my real world experiences. Cheers all!