BBK Longtubes are fine, most people will advise against them saying get SLP or some other brand, but they are really fine. I had them for 2 years on my GT and the guy I bought my car from had them on for 3 before that, They will tend to eventually rust, but as long as you don't live up north you really don't have to worry about it. Mine have been on the car for 5 years, and its barely speckling on the bottom.

And like said above, H vs. X is all preference. I like H pipes with flow masters, but other than that I would go X pipe every time.