3230 Channel Balance and top plastic piece

Thanks for contacting us. That top plastic piece is known as a top sash guide. Yours in particular looks like our 18-171. As for the balance, it's tough to say for sure based on your photos since I can't make out the nylon fittings that well, but start by looking at our S395-33. This comes with a 19-005 top and 15-001 bottom fitting and may be a good replacement option, as long as those fittings match.