One thing I am wondering about, is ls vtec much different from just a head swap? I know it involves replacing the oil pump with a stock gsr's, replacing the rods with ARP 8mm's, and I know it involves doing other small but important things like oil lines and such.

The probloem is, I have an 89 hatchback just rebuilt the d15 in it, and I also have a wrecked 95 ex coupe. Because I dont know if the ex block is any good I will just do a head swap. Do I need to change the pistons or reinforce the rods on the d15? I have also heard of people blowing their motors because the d15 pistons hit the d16 valves due to vtec overextending them. Did these people just screw up on timing, or use the wrong head gasket, or is this a problem I need to address?
Thanks,