Do you mean the Super Stealths, or mean that the newer Stealths are better than the initial ones released?

I have a pair of Stealths, bought last Fall. I bought the upgraded retainers and locks- and had my machinist inspect them. Everything was good: the valve job, the guide clearances, the installed valve heights and so on. Other than needing to be COMPLETELY cleaned of aluminium shavings and the 10 degree retainer upgrade (the 7 degree ones are tin..), they appear to be very well made.

Time will tell, once I get them on my motor.