Do video processors really work on rear proj. tv's

I have a Pioneer Elite Pro 610 HD rear projection HD tv with a 58 inch 16:9 screen. I desparately want to improve the video quality of the non-HD material on Direct-tv. I'm considering the Faroudja Native Rate Series scaler, but I'm not sure if the improvement will warrant the $3300.00 price. Any info or help would be greatly appreciated.

Thanks,

Craig