Have the heads checked over before you install them. A little bit of money spent now can avoid disasters later. This should be SOP for ALL parts no matter who builds them. Check and correct.
The valve job on a mass produced head will be less than perfect and you need to verify guide clearance so now would be the time to have a performance valve job done.
The earlier Stealth heads had valve seat inserts that hung into the ports. This doesn't cause a reliability issue but it does affect flow. If the newer versions haven't addressed this, a few minutes with a die grinder can fix it.
