Will they survive on the street?

 

Yes.

Just because titanium valves aren't the best street item (titanium us harder, but shatters easier it seems), doesn't mean that the retainers can't be used. Consider: Ti valves get used because they are light and can get good revs easier. However, after prolonged use (more than ~600 miles aka-NASCAR), they become prone to breaking. Slamming into the valve seat at 9000 rpm's isn't the friendliest thing for them, granted they use softer seats. There is nothing for the retainer to slam into, unless you are maxing out the distance between the guide boss and the retainer. So really, all it will end up doing is reducing the valve train mass to an extent. Go for it.