When it comes to tightening spark plugs, drain plugs, ect. on an aluminum engine, I trust "feel" over a torque wrench. I like to be able to feel how the gasket is compressing as the plug is tightened, and you loose some of that feedback using a torque wrench vs. standard ratchet.
Torque wrenches can go out of spec if not calibrated regularly, particularly in the lower ranges. And torque specs are quoted for a new engine, not one that has miles of heat expansion and may have had the threads over-orqued by a previous owner. I had to Heli-coil the oil drain plug hole on my friend's KLR a few years ago, after she dialed the torque wrench up to Kawasaki's recommendation and the threads immediately stripped out... the wrench never clicked.
Andy