The only way to be fairly confident that it helps is this:

Download a file without it. How long did it take?
Download the same file with it immediately after the first download is complete. How long did it take?

Speeds vary in Limewire while you're downloading a file...this method would allow you to determine an average speed.

What type of connection do you have?

We're a little skeptical because the Limewire accelerator has been examined by the developers, and they say it doesn't help. There are many reasons why your download speed could vary. Some people download very quickly at times and slowly at other times. It depends on your speed, the speed of the host, the bandwidth allocated by you and the host, your ISP, the number of sources, etc.

Cheers

Dano