L26's throw rods sometimes, but this is primarily with Turbo or xpz 6600 ron shift point builds. Nothing to worry about with your goals.
An XP/s1x setup on a 3.4 is not gonna make 320whp. You might get near 300, but even with high compression and a Gen V, I doubt it.
Ditch the double roller and the 130# springs. Get cheap 90# springs. They will make more power, and wont tear sh1t up in your valvetrain. Ls6 springs can take you to 6500rpm without any issues. And there's no need to shift higher with an XP, s1x. Put the saved money towards those 42# injectors and a tune.
