Umm... GReddy Evo and the Skunk2 Megapower have 60mm diameter piping. BUT what the GReddy has is 115 degree bends, not 90 degree bends like the stock (I'm unsure if Skunk2 has followed suit with this too)

So, if I'm to compare the exhausts, I see two that will perform nearly the same, like within 1hp of each other, but one that A) Looks better from every angle, and B) Does not make my car sound like an angry bumblebee in a coffee can.

That's where "looks" and "sounds" count.

My only complaint with a GReddy Evo is the use of aluminized steel, not stainless, so while that decreases weight, it makes it susceptible to salt-rot...