I have fully finned 97mm cylinders in my Carrera motor. I don't think any extra machining was required as such to make them fit.
I had the base of the cylinders machine as I was running thicker (0.5mm) base shims as well as the 0.5mm C2T head gaskets.
'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