Hey guys - after reading a previous thread about Nitro Trailers, I took a chance and ordered the following part(s) on etrailer.com:
Dexter Heavy Duty Suspension Upgrade Kit for Single Axle Trailers - Double Eye Springs - Item # K71-358-00
Without a doubt, this took nearly every ounce of squeak off of my trailer. I'm sure I'll have to re-grease regularly, but man, I am shocked at how quiet my trailer is now. Definitely worth it for $73.92!!
Installation was a little tricky, but if you know how to get around a trailer's leaf spring/axle and have the tools needed, it's worth the effort.