So, I have been doing a little research and it seems that the consensus is that four-point harnesses should NOT be used in regular cars that don't have roll bars and where the driver isn't wearing a helmet. I have just revised our product descriptions on our site to include these details but then I read that this may not be the case. What are your thoughts? Have you ever used four or five point harnesses in non-race cars?

There are some cars that I would argue that a three point belt restricts my movement to the point where its unsafe to wear.

You ask a good question... aside from the fact that it is generally illegal to wear a helmet while driving, I have never thought about the pros/cons of 4~5 point belts. In general, its my understanding that to a certain degree both of these require some caging to anchor the over the shoulders belts, as its my understanding that they should not be anchored to the floor.