1. They'll never stop contacting you. If you use them, be ready to purchase a car. The same logic goes for dealerships in general.
2. If you get a quote via TrueCar, just know that dealerships can still get around that too. A lot of people go to dealerships with the TrueCar quote like, "But TrueCar said...." and it almost never works out for them. TrueCar is more of a tool to help you negotiate your price better. Most dealerships will argue that the TrueCar quote applies to a specific car not all within a model.
The tip I always give people are the following:
-The car's invoice is anywhere from 6-10K under the sticker. -Dealerships usually put extras in the car to inflate the price (tint, pinstriping, etc.) They will try to charge you an extra $1000 for this. -Monthly payments are important but the bottom line is more important. -Seek financing from your bank or credit union first. They usually treat you better than outside financiers.