Anyone using one?

Here's an example COLEMAN MACHINE 22370 STEERING QUICKENER 2.0:1 $127.95 BUY ONLINE

One of the problems with these cars is the amount of steering input needed at slower, autocross speeds which makes it very difficult to get through a slolom quickly.

So I was wondering if anyone had used or is using one or might be able to enlighten me a bit about it.