At this point, it has been confirmed that the Gen Coupe has a 4b11 block. The rest is still up in the air and it has been speculated that at least the pistons, and head are different.
It will be a great platform to mod for the price. I think I had previously mentioned that Buschur Racing has ordered a turbo gen coupe and it will be one of the first delivered in the states. They have stated that they will be developing parts for it, and that there will be a gen coupe bracket in the next DSM shootout.