Sandy Mandel answers:

The coolant running through the throttle body does one thing and one thing only. It keeps the TB from 'icing up' in the winter. If you do little or no winter driving, yeah, all it does is heat up the incoming air, especially in summer. I've heard that 'bypassing' the TB with coolant line butt connectors and all can add a few HPs. And I'm pretty sure it is most beneficial in warm to hot weather. The only consequence I can think of is the TB ices up and won't thaw out enough to allow the engine to run, and also probably destroys 'cold operation' emissions. I'm considering doing this one (bypassing the throttlebody) to my '86, as I do little winter driving, and do not keep the car outside.

I actually have my throttle body by-passed. I went through the winter with no problems out of the car at all as far as freezing of the throttle plate goes. That's what the coolant is supposed to prevent. But unless you are going to be in very cold conditions through the winter I would suggest the by-pass. You can do it easily by buying a hose connector and taking the 2 hoses out of the throttle and connecting them straight together. No harm will be caused by this. It may have different results in every car but it actually helped mine on top end performance.