PorscheRoo

In my pursuit of a 930 I've been doing as much research as possible. Much of the literature I come across indicates caution in purchasing a grey market 930 (say '80 - '85) yet I see many available. They claim that these cars may be difficult to both register and insure. Assuming the original conversion was a quality job and the car has the appropriate certificates would it really be all that difficult to register and insure such a vehicle, say in California? Or, should one truely avoid such cars?