My Originals are out for overhaul. Being fitted with 2.350" intake. Because of the size and weight, we decided on hollow stems from Ferrea. They are galactic back order. My other option is Titanium. Valves and new copper seats are a $900 upgrade. I was told that the Ti valves would add a lot of life to the valves, springs and valve job. I'm leaning towards the upgrade. Any downside besides cost?