Their workmanship and welding is some of the worst I have seen. Out of the box warped flanges, incomplete welds, etc. I looked over 8-10 sets of new in the box headers for my Lightning and there was not one set I could bolt on with no issues. Their ports don't match up so well either. For me I would not use or recommend them. Bassani, Kooks, and a few others have much better quality. Unfortunately at this time none of them offer applications for the 4.0 v6.
i have had great experainces with hedman headers, my buddy has a set of hooker headers on his 'stang...havent really looked for headers for the taco yet...but if i did then i would def. go with true duals