I'm running the oem prop valve, which has been working excellent so far! We calculated that bias would shift to the rear 3%, which was acceptable since FC's were biased more than needed to the front anyway
The Carbotechs are really great pads, they're also on my to-try list. Glenn got me interested in them too

Where's the best place to buy them?
And yeah, I remember taking my car out to an auto-x with the hp+ for the first time... tiresmoke everywhere, I was lucky not to get any flat spots on the tires! Now I'm used to them, especially with even stickier tires hehe