Garrett--

The ratcheting car seat tightener I mentioned is the "MightyTite". Here's a web page link to a place that carries them, FYI. We bought ours at Toys 'r' Us, or their dedicated baby store, Babies 'r' Us.

The device wasn't available when we had our son (who's now 5), but we've had one for about 18 months now for our 2-yr old. Her seat is locked in rock-solid, & is more secure than I ever was able to get his, without the device.

When you put a car seat in, put your weight on it before you fasten & tighten the seat belt. That will compress the cushions more, & help you get a good, tight installation.

Depending on your upholstery, you may want to put a towel underneath the seat, too. It keeps it from cutting into them, especially leather. Spread out, it can also be somewhat of a "bib" to catch the inevitable spills, too. (Though, in that case, replacing it means removing & re-installing the car seat, or carrier base.)

Ed's advice about getting "professionally" checked is good. I have a number of friends on the local Fire department. One, their safety coordinator (EMT & RN), actually went with us to Babies 'r' Us & helped us choose a safe seat, then helped us install it properly. If you don't know someone like that, ask around at your local PD or FD.

David