consumer reports on diesel performance products?

I have a 2003 6.6 Duramax. I have already added a 4 inch exhaust which gave me about 2 more miles to the gallon on the highway not towing.There is alot of performance products out. Does consumer reports test these products? How do you know which product really works the best?

I found consumer reports to be so-so when it comes to testing products. Half the time their tests are not that accurate.