It sounds like it is a good rebuild. But the 600hp thing sounds kind of funny.

If cryotreated stock internals would save u from spending a lot of money on forged internals with the same reliability all of us would be doing it, looks like a scam to me

As stated by a vendor of this site. Cryo treating dosen't make it stronger, it causes it to wear better because it helps smooth out the surface bringing more atoms to the surface. Basically cryo treating gives you more surface area, it will not make the part stronger because it dosen't affect the temper of the material.