Clickers are nice. Overkill for tightening lugs tho. Valve cover, cam rocker mounts, all OK w/ 3/8". 1/2" is better for torquing injectors. Buy it based on your needs for the next job that you do. Don't lie to yourself, you'll end up w/ both anyways.

If you can wait till day after thanksgiving, craftsman torque wrenches were doobusters at sears, less than 1/2 price I think.