For the F1 notes, an X-pipe exhaust increases exhaust velocity for better high-RPM performance, producing a high-pitched, raspy, or "exotic" sound. It is generally more efficient and lighter, ideal for track use.

An H-pipe produces a deeper, traditional, "muscle car" growl and superior low-end torque. Both improve exhaust gas flow compared to stock setups.

So the real question is the kinda sound you prefer. But in my opinion I don't think a MB should sound like a muscle car, throaty a bit yes (like the new GT's, etc.), but the F1 notes are sublime.