[brucepick]

Good on reducing what looks like an excessive cold idle speed that was originally engineered into the car. If you increase the holes you left in the soda can material, you might not need to baby the accelerator to keep the engine going.

A grill block definitely helps. If you can find a way to read engine temp digitally I'd recommend that in conjunction with the grill block. That enables you to see if it's running a bit hotter than normal. It WILL run hotter, given enough grill block and warm or hot weather. Dash gauges are nice but typical factory ones don't give you precision information.

You can eliminate most cold idling by killing the engine when waiting at traffic lights. But you do need to be prompt about starting it up again, or you'll likely hear from the drivers behind you!