I have a colorado auto.. But the 5 speed is a bit notchy in the truck version too. There is a contact that I have looking into the durability of the 3.5 and the trans as well. He said the engine and trans are super durable. He just recommends changing out the clutch for high performance apps. There pushing the limits on the trans to see how far he can go. I think he's also developing rods for the I5, but they are forged in stock form already I think. Anyway I have faith in the 5 speed.. (that's my point haha)
Jay