I have a b18b and i was curious of how much stock valves could take? I figure the rushing in air and incomming gas on the intake valves should keep them cool. But as for the exhaust should i replace those? should i replace them all? Im not really sure what i want to do at this point. Comments, suggestions welcome

 

gsr valves are quite durable, if you widen the seat width on the contact surface it will make them even more durable

 

I would suggest atleast exhaust valves. But go oversized if possible. Headwork will offer the most gain for an LS head---i would pay more attention to that.
If your looking for some head work let me know.
Here is my LS head. I use +1mm Ferrea in and ex. 5 angle seats and backcut on the intake valves. Street ported and polished.