If I were you, I'd decide before spending thousands on the 996. You will not recover a fraction of a $12K service. In some cases, there could be buyers willing to pay an extra $2K for the IMS change.
Not sure I would. The factory put hundreds of thousands of miles of testing into the IMS they built. The aftermarket IMS is unproven and
AFAIK has a greater failure rate.
I'd recommend considering putting the big bucks you're considering for service into an extended warranty.