you can only go with an 82mm bore on the stock sleeves. and since he'll be going turbo i wouldnt recommend that. he'll need to resleeve it, which is going to be another ~$1000 then bore it to whatever he wants. i'd recommend 83mm so he has room for a re-bore if the cylinders ever get messed up. dont go above 10:1 c/r for a boosted setup.

tell your friend, instead of having bought this kit, he could have just bought the rods and pistons individually, all new bearings, and come out cheaper than what he paid for it.