Is it possible to buy them individually?

I have bought a head with skunk2 springs and retainers but i'm missing 4 of each!

Also is there anyway of telling if the springs are tuner or pro series from maybe uninstalled height or anything??

since its a street car, i might switch to steel retainers anyway

 

Call Skunk2... they'll help with those questions.. Titanium is fine as long as the valve seat pressures are ok. But its totally up to you.