Seems like a lot of hasstle for a little extra insurance. I'd just run oil through the water jackets if I was that paranoid, for a track car. For a street car that only sees occassional boost, I don't think all this is required and the turbo will last just being oil cooled and appropriate cool-down measures are taken, religiously. Just my 2c worth.
'89 911 Turbo Cab
Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition