One thing we have noticed here in our shop is the after market camshaft manufactures and vendors selling their products are not telling customers the entire truth about installing the more aggressive-higher lift camshafts in order to make a sale of their products.
Well this is not entirely true. Several things can happen when you install these cams, the valve spring harmonics are greatly increased to a level that can cause serious valve train issues, problems and damage, like the lifter ticking and failure, retainers hitting the tops of the valve stem seals and tearing the seals apart, bent-broken & dropped valves, valves hitting pistons, a real mess.
Your EVO valve springs and valve train geometry (as in any engine) is designed to open and close the valves at a particular time and lift and rate of lift.
Valves cannot not hold up to bouncing, flutter or slamming. When the valves cannot keep in proper time with the rest of the engine due to improper valve spring seat and open pressures your engine will experience "Valve Float", now this is when the costly problems begin to happen.
By simply installing the proper valve springs and retainers at the time of the camshaft upgrade your engine will run flawlessly and you can avoid costly, time consuming problems. The whole point of any upgrade is to enhance the performance of the car not to cause problem after problem.
It is far less expensive to replace all the needed components the first time then to rebuild or replace your entire engine later.