LIne doubler/scaler

Thank you for the info. This really helps, and exactly the info I was looking from someone knowledgeable.

It's unlikely a standard line doubler will do much for you as it really does not "double" the lines, it only de-interlaces them. Since you already have progressive scan--it's not going to do anything for you (some doublers do not accept progressive input). The Faroudja native resolution might help the picture quality significantly. It uses a fair amount of post processing along with a scaler (as opposed to a doubler) to improve the picture quality--of course you pay for it--Faroudja is not cheap--but does make great quality pictures.