Use it! If for nothing else but to dampen harmonics. Remember, this was the bandaid for the 3.9 non-countershaft V6. But being the 3.9 is essential a 5.2 with two cylinders lopped off, it fits and works. I believe it does offer more stable timing, and as JCC suggested, when on and off the power, really helps stabilize the chain backlash. It's cheap and works. Hell, even GM uses a tensioner on the LS motors!