I have never dealt with the Ultra Flo but they flow better than the Flomaster 40 but has the absorption muffler (deep sound) build to them. Those have attention.
When I added the X pipe it did quieten down exhaust but it was not like you couldn't hear it. Now when I nail it that didn't change... it's still loud. From what I have learned in the last couple of days I would go with the same set up I have but instead use the Ultra Flos. My neighbor has a 302 Ford T-bird that he installed Magnaflows .... the stock system sounded better! That car sounds like a mix between a 4 and 6 cylinder now. He has not mentioned his exhaust system to me ever again after he did that! lol He should have at least installed glass packs! LOL!