IMHO you might want to call and talk to one of the Porsche race shops--
EBS in Reno helped us with a 964 rebuild -- Titanium retainers were provided
with an EBS designed valve spring for race duty.
This is their contact info:
Porsche Racing Parts : Engine Performance Parts : Brake Parts : Used Porsche 356 : 911 : 912 : 914 : 944 : Porsche Boxster Parts : EBS Racing Inc.
(800) 462-3774 : M-F 8am-5pm PST)
Be aware, there are differing opinions about Ti or not...if you plan to run the
engine for 10-20 years then you may want the heavier retainers.
Regards,
